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Polynomials

Practice exam-style IB Math AA questions for Polynomials, aligned with the syllabus and grouped by topic.

Paper
Difficulty
Status
Level
Question 1
HL • Paper 1
Easy
Non Calculator

The polynomial function pp is defined by p(x)=k(x+2)2(x1)3p(x)=k(x+2)^2(x-1)^3, where kk is a constant. The graph of y=p(x)y=p(x) has yy-intercept 1212.

A

Find kk.

[2]
Write your answer here...
B

State the zeros of pp and their multiplicities.

[2]
Write your answer here...
C

State whether the graph crosses or touches the xx-axis at each zero.

[1]
Write your answer here...

0

Question 2
HL • Paper 1
Easy
Non Calculator

Consider the polynomial p(x)=x33x24x+12p(x)=x^3-3x^2-4x+12.

A

Show that x2x-2 is a factor of p(x)p(x).

[2]
Write your answer here...
B

Hence find all the zeros of pp.

[4]
Write your answer here...

0

Question 3
HL • Paper 1
Medium
Non Calculator

Let p(x)=x32x2+3x+6p(x)=x^3-2x^2+3x+6.

A

Show that x+1x+1 is a factor of p(x)p(x).

[2]
Write your answer here...
B

Hence factorize p(x)p(x) over R\mathbb{R}.

[3]
Write your answer here...

0

Question 4
HL • Paper 1
Medium
Non Calculator

The equation x3+px2+qx12=0x^3+px^2+qx-12=0 has roots \lpha\lpha, β\beta and γ\gamma. It is given that \lpha+β+γ=5\lpha+\beta+\gamma=5 and that one root is 33.

A

Find the value of pp.

[2]
Write your answer here...
B

Find qq and the other two roots.

[4]
Write your answer here...

0

Question 5
HL • Paper 1
Medium
Non Calculator

A monic quartic polynomial with real coefficients has roots 22, 1-1 and 1+2i1+2i.

A

Find the polynomial in expanded form.

[5]
Write your answer here...

0

Question 6
HL • Paper 1
Medium
Non Calculator

The equation 2x53x4+7x28=02x^5-3x^4+7x^2-8=0 has roots α1,α2,α3,α4,α5\alpha_1,\alpha_2,\alpha_3,\alpha_4,\alpha_5.

A

Find α1+α2+α3+α4+α5\alpha_1+\alpha_2+\alpha_3+\alpha_4+\alpha_5.

[2]
Write your answer here...
B

The roots of another equation are α1+2,α2+2,α3+2,α4+2,α5+2\alpha_1+2,\alpha_2+2,\alpha_3+2,\alpha_4+2,\alpha_5+2. Find the sum of the roots of this equation.

[2]
Write your answer here...
C

Find α1α2α3α4α5\alpha_1\alpha_2\alpha_3\alpha_4\alpha_5.

[1]
Write your answer here...

0

Question 7
HL • Paper 1
Medium
Non Calculator

Let p(x)=x4+mx3+nx27x+6p(x)=x^4+mx^3+nx^2-7x+6. It is given that x1x-1 is a factor of p(x)p(x) and that the remainder when p(x)p(x) is divided by x2x-2 is 1212.

A

Find the values of mm and nn.

[4]
Write your answer here...

0

Question 8
HL • Paper 2
Medium
Calculator Permitted

The polynomial p(x)=x4+ax3+bx28x+12p(x)=x^4+ax^3+bx^2-8x+12 has remainder 66 when divided by x1x-1, and remainder 3030 when divided by x+2x+2.

A

Use the remainder theorem to form two equations in aa and bb.

[2]
Write your answer here...
B

Find the value of aa and the value of bb.

[2]
Write your answer here...
C

Find the remainder when p(x)p(x) is divided by (x1)(x+2)(x-1)(x+2).

[2]
Write your answer here...

0

Question 9
HL • Paper 2
Medium
Calculator Permitted

The polynomial p(x)=x4+px3+qx2+rx+65p(x)=x^4+px^3+qx^2+rx+65 has real coefficients. Two of its roots are 2+i2+i and 32i3-2i.

A

Write down the other two roots of p(x)=0p(x)=0.

[1]
Write your answer here...
B

Find the values of pp, qq and rr.

[4]
Write your answer here...

0

Question 10
HL • Paper 2
Medium
Calculator Permitted

Let P(x)=x3+ax2+bx+cP(x)=x^3+ax^2+bx+c. When P(x)P(x) is divided by x23x+2x^2-3x+2, the remainder is 5x45x-4. When P(x)P(x) is divided by x3x-3, the remainder is 1111.

A

Write down three equations in aa, bb and cc.

[3]
Write your answer here...
B

Find aa, bb and cc.

[2]
Write your answer here...
C

Find P(4)P(4).

[1]
Write your answer here...

0

Question 11
HL • Paper 2
Medium
Calculator Permitted

A monic quartic polynomial has real coefficients, constant term 2020, and roots 1+2i1+2i, 22 and 22.

A

Write down the fourth root of the polynomial.

[1]
Write your answer here...
B

Determine the polynomial in expanded form.

[4]
Write your answer here...

0

Question 12
HL • Paper 2
Medium
Calculator Permitted

The polynomial p(x)=x3+ax2+bx+7p(x)=x^3+ax^2+bx+7 leaves the same remainder when divided by each of x1x-1, x3x-3 and x5x-5.

A

Find aa and bb.

[3]
Write your answer here...
B

Find the common remainder.

[1]
Write your answer here...
C

Hence factorize p(x)22p(x)-22.

[1]
Write your answer here...

0

Question 13
HL • Paper 2
Medium
Calculator Permitted

Consider the polynomial

p(x)=x45x37x2+41x30p(x)=x^4-5x^3-7x^2+41x-30
Quartic graph showing the polynomial curve crossing the x-axis at four real zeros.
A

Use your GDC to find the zeros of pp.

[2]
Write your answer here...
B

Hence solve the inequality p(x)0p(x)\le 0.

[3]
Write your answer here...

0

Question 14
HL • Paper 2
Medium
Calculator Permitted

A quartic polynomial PP has real coefficients and positive leading coefficient. It has a double root at x=1x=1, is divisible by x2+4x^2+4, and satisfies P(0)=12P(0)=12.

A

Determine P(x)P(x) in factorized form.

[3]
Write your answer here...
B

Write P(x)P(x) in expanded form.

[1]
Write your answer here...
C

State the real zeros of PP and their multiplicities.

[1]
Write your answer here...

0

Question 15
HL • Paper 1
Medium
Non Calculator

The polynomial p(x)=x4+kx33x2+lx+2p(x)=x^4+kx^3-3x^2+lx+2 has (x1)2(x-1)^2 as a factor.

A

Determine the values of kk and ll.

[5]
Write your answer here...

0

Question 16
HL • Paper 1
Medium
Non Calculator

The roots of p(x)=x32x25x+6p(x)=x^3-2x^2-5x+6 are α\alpha, β\beta and γ\gamma.

A

Find a monic polynomial equation with roots α+1\alpha+1, β+1\beta+1 and γ+1\gamma+1.

[5]
Write your answer here...

0

Question 17
HL • Paper 1
Medium
Non Calculator

Let p(x)p(x) be the monic cubic polynomial p(x)=x3+ax2+bx+cp(x)=x^3+ax^2+bx+c. The sum of the roots of p(x)=0p(x)=0 is 44. It is also given that x2x-2 is a factor of p(x)p(x) and that the remainder when p(x)p(x) is divided by x+1x+1 is 66.

A

Find aa, bb and cc.

[4]
Write your answer here...
B

Hence find the other two roots of p(x)=0p(x)=0.

[2]
Write your answer here...

0

Question 18
HL • Paper 2
Medium
Calculator Permitted

Consider the polynomial

p(x)=x54x4+2x3+10x227x+18p(x)=x^5-4x^4+2x^3+10x^2-27x+18
A

Use your GDC to find all the real zeros of pp.

[2]
Write your answer here...
B

Hence factorize p(x)p(x) over R\mathbb{R}.

[3]
Write your answer here...
C

Use the product of the roots to verify that the factorization is consistent with the constant term of p(x)p(x).

[1]
Write your answer here...

0

Question 19
HL • Paper 2
Medium
Calculator Permitted

The graph of y=f(x)y=f(x), where

f(x)=x44x32x2+12x+5f(x)=x^4-4x^3-2x^2+12x+5

intersects a horizontal line y=cy=c.

Quartic curve with stationary points marked.
A

Find the coordinates of the stationary points of the graph of y=f(x)y=f(x).

[3]
Write your answer here...
B

State the range of values of cc for which f(x)=cf(x)=c has exactly four distinct real roots.

[1]
Write your answer here...
C

State the values of cc for which f(x)=cf(x)=c has exactly two distinct real roots.

[2]
Write your answer here...

0

Question 20
HL • Paper 2
Medium
Calculator Permitted

The cubic polynomial p(x)=x33x2+kx+4p(x)=x^3-3x^2+kx+4 has a repeated root.

A

Find the value of kk.

[3]
Write your answer here...
B

Hence factorize p(x)p(x) completely over R\mathbb{R}.

[2]
Write your answer here...

0

Question 21
HL • Paper 2
Medium
Calculator Permitted

The polynomial

p(x)=2x57x4+ax3+bx2+cx75p(x)=2x^5-7x^4+ax^3+bx^2+cx-75

has real coefficients. Four of its roots are 2+i2+i, 2i2-i, 1-1 and 33.

A

Find the fifth root of p(x)=0p(x)=0.

[3]
Write your answer here...
B

Verify your answer using the product of the roots.

[2]
Write your answer here...

0

Question 22
HL • Paper 1
Medium
Non Calculator

A monic quartic polynomial PP has real coefficients and is divisible by x22x+5x^2-2x+5. The remainders when P(x)P(x) is divided by x1x-1 and by x+1x+1 are 1212 and 7272 respectively.

A
I.

Write P(x)P(x) in the form (x22x+5)(x2+px+q)(x^2-2x+5)(x^2+px+q). Use the given remainders to form two equations in pp and qq.

[3]
Write your answer here...
II.

Hence determine pp and qq.

[1]
Write your answer here...
B
I.

Factorize P(x)P(x) over R\mathbb{R}.

[2]
Write your answer here...
II.

Find all the roots of P(x)=0P(x)=0.

[4]
Write your answer here...

0

Question 23
HL • Paper 1
Medium
Non Calculator

A polynomial function pp of degree 55 has exactly two distinct zeros. The zero at x=2x=-2 has multiplicity 22, and the zero at x=1x=1 has multiplicity 33. It is also given that p(0)=16p(0)=16. Define q(x)=p(2x1)q(x)=p(2x-1).

A
I.

Find p(x)p(x) in factorized form.

[3]
Write your answer here...
II.

State whether the graph of y=p(x)y=p(x) crosses or touches the xx-axis at each zero.

[1]
Write your answer here...
B
I.

Find the zeros of qq and state their multiplicities.

[3]
Write your answer here...
II.

Find q(0)q(0).

[2]
Write your answer here...

0

Question 24
HL • Paper 1
Medium
Non Calculator

A cubic polynomial f(x)=ax3+bx2+cx+df(x)=ax^3+bx^2+cx+d satisfies

f(0)=1,f(1)=1,f(2)=3,f(3)=13f(0)=1,\quad f(1)=1,\quad f(2)=3,\quad f(3)=13
A
I.

Use the given values to form equations for aa, bb, cc and dd.

[2]
Write your answer here...
II.

Find f(x)f(x).

[3]
Write your answer here...
B
I.

Find f(4)f(4).

[1]
Write your answer here...
II.

Factorize f(x)1f(x)-1 completely over R\mathbb{R}, and hence state the roots of f(x)=1f(x)=1.

[3]
Write your answer here...

0

Question 25
HL • Paper 1
Medium
Non Calculator

Let p(x)=x43x3+ax2+bx+5p(x)=x^4-3x^3+ax^2+bx+5. The remainder when p(x)p(x) is divided by x1x-1 is 44, and the remainder when p(x)p(x) is divided by x+2x+2 is 6161.

A

Find the values of aa and bb.

[4]
Write your answer here...
B

Find the remainder when p(x)p(x) is divided by x2+x2x^2+x-2.

[3]
Write your answer here...

0

Question 26
HL • Paper 1
Medium
Non Calculator

The equation x38x2+kx12=0x^3-8x^2+kx-12=0 has roots \lpha\lpha, β\beta and γ\gamma. It is given that γ=\lpha+β\gamma=\lpha+\beta.

A

Find the value of γ\gamma.

[2]
Write your answer here...
B

Find kk and the other two roots.

[4]
Write your answer here...

0

Question 27
HL • Paper 2
Medium
Calculator Permitted

A monic quartic polynomial pp has real coefficients. Two of the roots of p(x)=0p(x)=0 are 1+2i1+2i and 22. The sum of all four roots is 77 and the product of all four roots is 3030.

A
I.

Write down the conjugate non-real root.

[1]
Write your answer here...
II.

Find the remaining real root.

[3]
Write your answer here...
B
I.

Determine p(x)p(x) in expanded form.

[3]
Write your answer here...
II.

Let q(x)=p(x+1)q(x)=p(x+1). State the roots of q(x)=0q(x)=0.

[1]
Write your answer here...

0

Question 28
HL • Paper 2
Medium
Calculator Permitted

For real aa, define pa(x)=x4+ax36x2+4x+8p_a(x)=x^4+ax^3-6x^2+4x+8.

A
I.

Show that if x=2x=2 is a repeated root of pa(x)=0p_a(x)=0, then a=1a=-1.

[3]
Write your answer here...
II.

Verify that x=2x=2 is a repeated root when a=1a=-1.

[1]
Write your answer here...
B
I.

Factorize p1(x)p_{-1}(x) completely over R\mathbb{R}.

[2]
Write your answer here...
II.

State the zeros of p1p_{-1} and their multiplicities, and describe the behaviour of the graph at each zero.

[2]
Write your answer here...

0

Question 29
HL • Paper 2
Medium
Calculator Permitted

The equation

x3+ax2+44x48=0x^3+ax^2+44x-48=0

has three positive real roots which are in arithmetic progression.

A

Let the roots be mdm-d, mm and m+dm+d. Show that mm satisfies m322m+24=0m^3-22m+24=0.

[3]
Write your answer here...
B

Use your GDC to find the roots of the original equation.

[2]
Write your answer here...
C

Find the value of aa.

[1]
Write your answer here...

0

Question 30
HL • Paper 1
Hard
Non Calculator

The monic cubic polynomial p(x)=x3+ax2+bx27p(x)=x^3+ax^2+bx-27 has roots 3r\frac{3}{r}, 33 and 3r3r, where r0r\ne 0. It is given that the remainder when p(x)p(x) is divided by x1x-1 is 2-2.

A
I.

Use the product of the roots to justify that 33 is the middle root in this geometric sequence.

[2]
Write your answer here...
II.

Show that r+1r=3r+\frac{1}{r}=3.

[3]
Write your answer here...
B
I.

Hence find the values of aa and bb.

[3]
Write your answer here...
II.

Find the three roots of p(x)=0p(x)=0.

[4]
Write your answer here...

0

Question 31
HL • Paper 1
Hard
Non Calculator

Let P(x)=x4+ax3+bx2+cx+10P(x)=x^4+ax^3+bx^2+cx+10, where a,b,cRa,b,c\in\mathbb{R}. It is given that x2+1x^2+1 is a factor of P(x)P(x) and that the remainder when P(x)P(x) is divided by x1x-1 is 1010.

A
I.

Use the factor theorem to obtain two equations involving aa, bb and cc.

[3]
Write your answer here...
II.

Find aa, bb and cc.

[3]
Write your answer here...
B
I.

Find the remainder when P(x)P(x) is divided by x23x+2x^2-3x+2.

[3]
Write your answer here...
II.

Hence show that x23x+2x^2-3x+2 is a factor of P(x)10P(x)-10.

[1]
Write your answer here...

0

Question 32
HL • Paper 1
Hard
Non Calculator

Let p(x)=x35x2+2x+8p(x)=x^3-5x^2+2x+8. The roots of p(x)=0p(x)=0 are denoted by α\alpha, β\beta and γ\gamma. A new polynomial equation has roots 1α1\frac{1}{\alpha-1}, 1β1\frac{1}{\beta-1} and 1γ1\frac{1}{\gamma-1}.

A
I.

Show that x4x-4 is a factor of p(x)p(x).

[2]
Write your answer here...
II.

Hence factorize p(x)p(x) completely over R\mathbb{R}.

[3]
Write your answer here...
B
I.

Write down the three roots of the new equation.

[2]
Write your answer here...
II.

Determine a polynomial equation with integer coefficients having these roots.

[4]
Write your answer here...

0

Question 33
HL • Paper 1
Hard
Non Calculator

Let

p(x)=x52x4+ax3+bx2+cx+12p(x)=x^5-2x^4+ax^3+bx^2+cx+12

where a,b,cRa,b,c\in\mathbb{R}. It is given that x24x^2-4 is a factor of p(x)p(x) and that the remainder when p(x)p(x) is divided by x+1x+1 is 3030.

A
I.

Use the factor theorem to form three equations in aa, bb and cc.

[3]
Write your answer here...
II.

Solve these equations to find aa, bb and cc.

[3]
Write your answer here...
B
I.

Hence factorize p(x)p(x) over R\mathbb{R}.

[4]
Write your answer here...
II.

Find all the roots of p(x)=0p(x)=0.

[3]
Write your answer here...

0

Question 34
HL • Paper 1
Hard
Non Calculator

The monic cubic polynomial p(x)=x3+ax2+bx80p(x)=x^3+ax^2+bx-80 has three roots which are consecutive terms of an arithmetic sequence. It is given that the sum of the roots is 1515.

A
I.

Find aa.

[2]
Write your answer here...
II.

Let the roots be mdm-d, mm and m+dm+d. Find the three roots of p(x)=0p(x)=0.

[4]
Write your answer here...
B
I.

Find bb.

[2]
Write your answer here...
II.

second monic cubic equation has roots equal to the squares of the roots of p(x)=0p(x)=0. Determine this equation.

[4]
Write your answer here...

0

Question 35
HL • Paper 1
Hard
Non Calculator

Let p(x)=x34x2+x+6p(x)=x^3-4x^2+x+6. The roots of p(x)=0p(x)=0 are α\alpha, β\beta and γ\gamma. A polynomial equation q(x)=0q(x)=0 has roots 1α\frac{1}{\alpha}, 1β\frac{1}{\beta} and 1γ\frac{1}{\gamma}.

A
I.

Show that x+1x+1 is a factor of p(x)p(x).

[2]
Write your answer here...
II.

Factorize p(x)p(x) completely over R\mathbb{R}.

[2]
Write your answer here...
B
I.

Write down the roots of q(x)=0q(x)=0.

[2]
Write your answer here...
II.

Find a polynomial equation with integer coefficients for q(x)=0q(x)=0.

[4]
Write your answer here...

0

Question 36
HL • Paper 1
Hard
Non Calculator

A monic quartic polynomial PP has real coefficients. Two of its roots are 2+i2+i and 2i2-i. The other two roots are equal. The coefficient of x3x^3 in P(x)P(x) is 8-8.

A
AI.

Let the repeated root be rr. Show that r=2r=2.

[3]
Write your answer here...
AII.

Write P(x)P(x) in factorized form over R\mathbb{R}.

[1]
Write your answer here...
B
BI.

Find P(x)P(x) in expanded form.

[3]
Write your answer here...
BII.

Find the remainder when P(x)P(x) is divided by x+1x+1.

[2]
Write your answer here...
BIII.

State the product of all four roots of P(x)=0P(x)=0 and verify that it is consistent with the expanded polynomial.

[1]
Write your answer here...

0

Question 37
HL • Paper 2
Hard
Calculator Permitted

Consider the polynomial p(x)=x5+ax4+bx37x2+cx+10p(x)=x^5+ax^4+bx^3-7x^2+cx+10, where aa, bb and cc are real constants. It is given that x21x^2-1 is a factor of p(x)p(x) and that the remainder when p(x)p(x) is divided by x2x-2 is 1212.

A
I.

Use the factor theorem and the remainder theorem to form three equations in aa, bb and cc.

[3]
Write your answer here...
II.

Hence determine aa, bb and cc.

[2]
Write your answer here...
B
I.

Hence write p(x)p(x) as the product of x21x^2-1 and a cubic polynomial.

[2]
Write your answer here...
II.

Use your GDC to find all real zeros of pp, giving your answers to three significant figures.

[2]
Write your answer here...
III.

State the number of non-real roots of p(x)=0p(x)=0.

[1]
Write your answer here...

0

Question 38
HL • Paper 2
Hard
Calculator Permitted

The polynomial p(x)=x415x3+70x2120x+64p(x)=x^4-15x^3+70x^2-120x+64 has roots α1\alpha_1, α2\alpha_2, α3\alpha_3 and α4\alpha_4. A new polynomial qq has roots βi=1+1αi\beta_i=1+\dfrac{1}{\alpha_i}, for i=1,2,3,4i=1,2,3,4.

A
I.

Use your GDC or otherwise to find the roots of p(x)=0p(x)=0.

[1]
Write your answer here...
II.

Write down the four roots of q(x)=0q(x)=0.

[2]
Write your answer here...
B
I.

Find the sum and product of the roots of q(x)=0q(x)=0.

[2]
Write your answer here...
II.

Determine the monic polynomial q(x)q(x) in expanded form.

[3]
Write your answer here...

0

Question 39
HL • Paper 2
Hard
Calculator Permitted

A cubic polynomial has leading coefficient 22. When divided by x3x-3 and by x+2x+2, the remainder is 00 in each case. When divided by x1x-1, the remainder is 44.

A
I.

Write the polynomial in the form p(x)=2(x3)(x+2)(xr)p(x)=2(x-3)(x+2)(x-r) and find rr.

[3]
Write your answer here...
II.

Hence write p(x)p(x) in expanded form.

[1]
Write your answer here...
B
I.

Use your graphing calculator to solve p(x)>0p(x)>0.

[3]
Write your answer here...
II.

Find the sum of the roots of p(x)=0p(x)=0 and verify it using the coefficient of x2x^2.

[1]
Write your answer here...

0

Question 40
HL • Paper 2
Hard
Calculator Permitted

A symmetric bridge arch is modelled by the polynomial h(x)=ax4+bx2+ch(x)=ax^4+bx^2+c, where hh is the height in metres and xx is the horizontal distance in metres from the centre of the arch. The arch is 66 metres high at its centre. At x=4x=4, the arch meets the ground and has gradient 5-5.

Quartic bridge arch with centre height, ground intercepts, and the point at x=4.
A
I.

Write down the value of cc.

[1]
Write your answer here...
II.

Use the information at x=4x=4 to find aa and bb.

[3]
Write your answer here...
B
I.

Find the width of the arch at a height of 33 metres.

[3]
Write your answer here...
II.

State the mathematical reason why the two values of xx found in part (b)(i) are opposite in sign.

[1]
Write your answer here...

0

Question 41
HL • Paper 2
Hard
Calculator Permitted

Let f(x)=x44x2+1f(x)=x^4-4x^2+1. The graph of y=f(x)y=f(x) is intersected by the horizontal line y=cy=c. The graph includes an illustrative horizontal line at y=1y=-1 (that is, c=1c=-1); it is not intended to represent a general value of cc.

Graph of $y=x^4-4x^2+1$ with stationary points marked and an illustrative horizontal line at $y=-1$ (that is, $c=-1$).
A
I.

Find the coordinates of the stationary points of y=f(x)y=f(x).

[3]
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II.

Classify the stationary point at x=0x=0.

[1]
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B
I.

Determine the range of values of cc for which f(x)=cf(x)=c has four distinct real roots.

[2]
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II.

Determine the values of cc for which f(x)=cf(x)=c has exactly two distinct real roots.

[2]
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0

Question 42
HL • Paper 2
Hard
Calculator Permitted

A monic polynomial PP of degree 55 has real coefficients. It has a double root at x=1x=1, a root at x=3x=-3, and a non-real root 1+3i1+3i.

A
I.

Write down the remaining non-real root.

[1]
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II.

Write P(x)P(x) in factorized form over R\mathbb{R}.

[3]
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B
I.

Expand P(x)P(x).

[2]
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II.

Use Vieta's formulae to verify the sum and product of the five roots.

[2]
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0

Question 43
HL • Paper 3
Hard
Calculator Permitted

The diagram shows the family of quartic polynomial functions

ft(x)=x42tx2+1,tRf_t(x)=x^4-2tx^2+1, \qquad t\in \mathbb{R}

The value of tt changes the number and nature of the real zeros of the graph.

Representative graphs of the quartic family for different values of t.
A
I.

Show that the equation ft(x)=0f_t(x)=0 may be written as a quadratic equation in uu, where u=x2u=x^2.

[2]
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II.

Find the roots of this quadratic equation in terms of tt.

[3]
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B

Determine the values of tt for which ft(x)=0f_t(x)=0 has four distinct real roots.

[3]
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C
I.

Find all repeated real roots of ft(x)=0f_t(x)=0 and the corresponding values of tt.

[3]
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II.

State the multiplicity of each real root when t=1t=1.

[1]
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D

For t>1t>1, let the four real roots be b-b, a-a, aa and bb, where 0<a<b0<a<b. Show that ab=1ab=1, and hence find a+ba+b in terms of tt.

[2]
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0

Question 44
HL • Paper 3
Hard
Calculator Permitted

A monic cubic polynomial PP is to be constructed from information about remainders. It is given that

P(x)=x3+ax2+bx+cP(x)=x^3+ax^2+bx+c

The graph of y=P(x)y=P(x) is shown together with the horizontal line y=4y=4.

Graph of P(x) and the horizontal line y=4.
A
I.

The remainder when P(x)P(x) is divided by x1x-1 is 44. Write down the corresponding equation in aa, bb and cc.

[1]
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II.

The remainder when P(x)P(x) is divided by x+2x+2 is 18-18. Write down the corresponding equation in aa, bb and cc.

[1]
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III.

It is also given that P(0)=2P(0)=2. Find aa, bb and cc.

[2]
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B

Let Q(x)=3P(x)12Q(x)=3P(x)-12. Show that

Q(x)=3x35x2+8x6Q(x)=3x^3-5x^2+8x-6
[2]
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C
I.

Use your GDC to find the real root of Q(x)=0Q(x)=0.

[2]
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II.

Explain what this root represents on the graph of y=P(x)y=P(x).

[2]
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D

second monic cubic RR satisfies R(x)4=(xs)2(xt)R(x)-4=(x-s)^2(x-t), where sts\ne t. Given that R(1)=4R(1)=4 and R(2)=14R(-2)=-14, determine all possible pairs (s,t)(s,t).

[3]
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0

Question 45
HL • Paper 3
Hard
Calculator Permitted

A polynomial equation has roots α1,α2,,αn\alpha_1,\alpha_2,\ldots,\alpha_n. A new equation is formed by translating each root 33 units to the right. This question investigates how the coefficients change under this transformation.

A simple flow diagram showing a polynomial $p(x)$ with roots $\alpha_i$ transformed to a polynomial $q(x)$ with roots $\alpha_i+3$.
A
I.

The monic cubic p(x)=x36x2+11x6p(x)=x^3-6x^2+11x-6 has roots α\alpha, β\beta and γ\gamma. Write down α+β+γ\alpha+\beta+\gamma and αβγ\alpha\beta\gamma.

[2]
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II.

Find the monic cubic whose roots are α+3\alpha+3, β+3\beta+3 and γ+3\gamma+3.

[2]
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B

monic polynomial p(x)p(x) of degree nn has roots α1,α2,,αn\alpha_1,\alpha_2,\ldots,\alpha_n and coefficient of xn1x^{n-1} equal to AA. Find the coefficient of xn1x^{n-1} in the monic polynomial whose roots are α1+3,α2+3,,αn+3\alpha_1+3,\alpha_2+3,\ldots,\alpha_n+3.

[3]
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C
I.

Let p(x)=x44x3+kx2+mx+9p(x)=x^4-4x^3+kx^2+mx+9. Given that the roots of p(x)=0p(x)=0 are translated 33 units to the right to form q(x)q(x), find the coefficient of x3x^3 in q(x)q(x).

[2]
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II.

If the product of the roots of q(x)=0q(x)=0 is 00, show that one root of p(x)=0p(x)=0 is 3-3.

[3]
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0

Question 46
HL • Paper 3
Hard
Calculator Permitted

A polynomial PP is divided by a quadratic divisor. The quotient and remainder are represented in the diagram by the identity

P(x)=(x24)Q(x)+R(x)P(x)=(x^2-4)Q(x)+R(x)

where the degree of RR is less than 22.

A polynomial division identity diagram with boxes for dividend $P(x)$, divisor $x^2-4$, quotient $Q(x)$ and linear remainder $R(x)$.
A
I.

Explain why R(x)R(x) may be written in the form mx+nmx+n.

[1]
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II.

It is given that P(2)=9P(2)=9 and P(2)=7P(-2)=-7. Find R(x)R(x).

[3]
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B

Let

P(x)=x4+ax3+bx2+cx+dP(x)=x^4+ax^3+bx^2+cx+d

It is also given that x1x-1 and x+3x+3 are factors of P(x)P(x), and that the remainder on division by x24x^2-4 is the function found in part (a). Determine aa, bb, cc and dd.

[5]
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C
I.

Hence factorize P(x)P(x) over R\mathbb{R}.

[2]
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II.

State the zeros of PP.

[1]
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0

Question 47
HL • Paper 3
Hard
Calculator Permitted

The points (0,P(0))(0,P(0)), (1,P(1))(1,P(1)) and (2,P(2))(2,P(2)) lie on a straight line. It is known that P(0)=5P(0)=5, P(1)=9P(1)=9 and P(2)=13P(2)=13.

Given points and the cubic polynomial curve on the same axes.
A
I.

Find the linear polynomial R(x)R(x) passing through the three points (0,5)(0,5), (1,9)(1,9) and (2,13)(2,13).

[2]
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II.

Explain why P(x)R(x)P(x)-R(x) has factors xx, x1x-1 and x2x-2.

[2]
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B

Assume PP is a monic cubic. Determine P(x)P(x).

[3]
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C
I.

Use your GDC to find the real zero of PP.

[2]
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II.

Explain why the other two roots are non-real.

[1]
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D

Find the remainder when P(x)P(x) is divided by x23x+2x^2-3x+2.

[2]
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0

Question 48
HL • Paper 1
Hard
Non Calculator

Consider the reciprocal polynomial equation

2x49x3+14x29x+2=02x^4-9x^3+14x^2-9x+2=0
A
AI.

Show that x=0x=0 is not a root, and divide the equation by x2x^2.

[2]
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AII.

Let u=x+1xu=x+\frac{1}{x}. Show that uu satisfies 2u29u+10=02u^2-9u+10=0.

[3]
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B
BI.

Solve the quadratic equation for uu.

[2]
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BII.

Hence solve the original quartic equation.

[3]
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0

Question 49
HL • Paper 1
Hard
Non Calculator

Let p(x)=x4+ax3+bx22x+3p(x)=x^4+ax^3+bx^2-2x+3, where a,bRa,b\in\mathbb{R}. The roots of p(x)=0p(x)=0 are α1,α2,α3,α4\alpha_1,\alpha_2,\alpha_3,\alpha_4.

A
I.

Show that the roots of p(x1)=0p(x-1)=0 are α1+1,α2+1,α3+1,α4+1\alpha_1+1,\alpha_2+1,\alpha_3+1,\alpha_4+1.

[2]
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II.

Given that the sum of the roots of p(x1)=0p(x-1)=0 is 1010, find aa.

[2]
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B
I.

Show that the product of the roots of p(x+1)=0p(x+1)=0 is p(1)p(1).

[2]
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II.

Given that this product is 1212, find bb.

[3]
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0

Question 50
HL • Paper 2
Hard
Calculator Permitted

Let P(x)=x4+ax3+bx2+cx+dP(x)=x^4+ax^3+bx^2+cx+d. When P(x)P(x) is divided by x21x^2-1, the remainder is 3x+43x+4. When P(x)P(x) is divided by x2+1x^2+1, the remainder is 2x52x-5.

A
I.

Use the first division statement to obtain two equations in aa, bb, cc and dd.

[2]
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II.

Use the second division statement to obtain two further equations.

[2]
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III.

Hence determine aa, bb, cc and dd.

[1]
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B
I.

Write P(x)P(x) explicitly.

[1]
Write your answer here...
II.

Use your GDC to find the real zeros of PP, giving your answers to three significant figures.

[2]
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III.

State the number of non-real roots of P(x)=0P(x)=0.

[1]
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0

Question 51
HL • Paper 2
Hard
Calculator Permitted

The equation x314x2+kx64=0x^3-14x^2+kx-64=0 has three positive real roots which form a geometric progression. Let the roots be ar\dfrac{a}{r}, aa and arar, where a>0a>0 and r>1r>1.

A
I.

Show that a=4a=4.

[2]
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II.

Hence show that 2r25r+2=02r^2-5r+2=0.

[2]
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B
I.

Find the three roots of the cubic equation.

[2]
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II.

Determine the value of kk.

[2]
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0

Question 52
HL • Paper 2
Hard
Calculator Permitted

For real aa, consider the cubic polynomial fa(x)=x33x+af_a(x)=x^3-3x+a.

Family of translated cubics y=x^3-3x+a.
A
I.

Find the coordinates of the stationary points of y=fa(x)y=f_a(x) in terms of aa.

[3]
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II.

State which stationary point is a local maximum.

[1]
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B
I.

Determine the range of values of aa for which fa(x)=0f_a(x)=0 has three distinct real roots.

[2]
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II.

For a=1a=1, use your GDC to find the three roots of fa(x)=0f_a(x)=0.

[2]
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0

Question 53
HL • Paper 2
Hard
Calculator Permitted

Let p(x)=x53x4+2x3+5x27x+4p(x)=x^5-3x^4+2x^3+5x^2-7x+4. The roots of p(x)=0p(x)=0 are α1,α2,α3,α4,α5\alpha_1,\alpha_2,\alpha_3,\alpha_4,\alpha_5. For x0x\ne0, define q(x)=x5p(1x)q(x)=x^5p\left(\dfrac{1}{x}\right); let qq be the polynomial extension of this expression to x=0x=0.

A

Part (a)

I.

Find q(x)q(x) in expanded form.

[2]
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II.

Prove that the roots of q(x)=0q(x)=0 are 1α1,1α2,1α3,1α4,1α5\dfrac{1}{\alpha_1},\dfrac{1}{\alpha_2},\dfrac{1}{\alpha_3},\dfrac{1}{\alpha_4},\dfrac{1}{\alpha_5}.

[2]
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B

Part (b)

I.

Find i=151αi\displaystyle\sum_{i=1}^{5}\dfrac{1}{\alpha_i}.

[2]
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II.

Find i=151αi\displaystyle\prod_{i=1}^{5}\dfrac{1}{\alpha_i}.

[2]
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0

Question 54
HL • Paper 3
Hard
Calculator Permitted

A reciprocal quartic is a quartic polynomial whose coefficients read the same forwards and backwards. Consider

P(x)=x4+ax3+bx2+ax+1P(x)=x^4+ax^3+bx^2+ax+1

where a,bRa,b\in \mathbb{R}. The graph shown is for one choice of aa and bb.

Graph of a reciprocal quartic example.
A
I.

For x0x\ne 0, show that P(x)=0P(x)=0 is equivalent to

x2+ax+b+a1x+1x2=0x^2+ax+b+a\frac{1}{x}+\frac{1}{x^2}=0
[2]
Write your answer here...
II.

Let u=x+1xu=x+\frac{1}{x}. Show that P(x)=0P(x)=0 becomes

u2+au+(b2)=0u^2+au+(b-2)=0
[3]
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B

For a=5a=-5 and b=7b=7, find all roots of P(x)=0P(x)=0 exactly.

[5]
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C
I.

Explain why a real value of u=x+1xu=x+\frac{1}{x} can produce real values of xx only when u2u\le -2 or u2u\ge 2.

[2]
Write your answer here...
II.

Hence state the number of real roots of P(x)=0P(x)=0 when the two roots of u2+au+(b2)=0u^2+au+(b-2)=0 are 33 and 1-1.

[1]
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D

Suppose P(x)=0P(x)=0 has roots rr, 1r\frac{1}{r}, ss and 1s\frac{1}{s}, where r,s0r,s\ne 0. Use the product of the roots to justify why the constant term of P(x)P(x) is 11.

[2]
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0

Question 55
HL • Paper 3
Hard
Calculator Permitted

A sensor response is modelled by a cubic polynomial S(x)S(x) on the interval 0x60\le x\le 6. The graph appears to touch the xx-axis at x=2x=2 and cross it at x=5x=5. A data table gives the additional value S(0)=20S(0)=20.

Cubic sensor-response curve on 0 ≤ x ≤ 6.
A
I.

Explain why S(x)S(x) can be written in the form k(x2)2(x5)k(x-2)^2(x-5).

[2]
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II.

Use S(0)=20S(0)=20 to find kk.

[2]
Write your answer here...
B

Find S(x)S(x) in expanded form.

[2]
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C
I.

horizontal threshold line y=hy=h is used. Use your GDC to find the local maximum value of S(x)S(x) on 0x60\le x\le 6.

[2]
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II.

State the number of solutions of S(x)=hS(x)=h in 0x60\le x\le 6 when 0<h<40<h<4.

[2]
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D

The model is modified to T(x)=S(x)+mT(x)=S(x)+m. Determine the range of mm for which T(x)=0T(x)=0 has exactly two distinct real roots.

[3]
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0

Question 56
HL • Paper 3
Hard
Calculator Permitted

A monic quintic polynomial PP has real coefficients. Two of its roots are 1+2i1+2i and 3i3-i. The remaining real root is denoted by rr.

AI.

Write down two other non-real roots of P(x)=0P(x)=0.

[1]
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AII.

Find the product of the four non-real roots.

[2]
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B

The constant term of P(x)P(x) is 400-400. Find rr.

[3]
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CI.

Find P(x)P(x) in factorized form over R\mathbb{R}.

[3]
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CII.

Find the coefficient of x4x^4 in P(x)P(x).

[2]
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D

Another monic quintic with the same four non-real roots has coefficient of x4x^4 equal to 13-13. Determine its constant term.

[3]
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0

Question 57
HL • Paper 3
Hard
Calculator Permitted

The roots of a monic cubic polynomial are positive and in geometric progression. Let the roots be mr\frac{m}{r}, mm and mrmr, where m>0m>0 and r>1r>1, so that they are in increasing order as shown.

A number-line diagram showing three positive roots ordered as $m/r$, $m$, and $mr$, with spacing not necessarily equal.
A
I.

Show that the product of the three roots is m3m^3.

[1]
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II.

The polynomial is x3Ax2+Bx64x^3-Ax^2+Bx-64. Find mm.

[2]
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III.

Express AA and BB in terms of rr.

[2]
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B

Hence show that B=4AB=4A for any such cubic.

[2]
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C
I.

Consider x321x2+84x64=0x^3-21x^2+84x-64=0. Verify that its positive roots are in geometric progression.

[2]
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II.

Find the common ratio of the progression.

[2]
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D

Use your GDC to determine whether x318x2+72x64=0x^3-18x^2+72x-64=0 has three positive roots in geometric progression. Justify your answer.

[3]
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0

Question 58
HL • Paper 3
Hard
Calculator Permitted

A sequence of values is generated by a polynomial function p(n)p(n), where nn is a positive integer. The table shows values of p(n)p(n) and successive differences.

nn

p(n)p(n)

First diff

Second diff

Third diff

1

0

6

12

6

2

6

18

18

6

3

24

36

24

4

60

60

5

120

A
I.

The values p(1)=0p(1)=0, p(2)=6p(2)=6, p(3)=24p(3)=24 and p(4)=60p(4)=60 are given. Explain why these values are consistent with a cubic polynomial whose constant third difference is 66.

[2]
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II.

Write down the leading coefficient of this cubic polynomial.

[2]
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B

Let p(x)=x3+ax2+bx+cp(x)=x^3+ax^2+bx+c. Use the given values to determine p(x)p(x).

[4]
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C
I.

Factorize p(x)p(x) completely over R\mathbb{R}.

[1]
Write your answer here...
II.

Hence state all integer roots of p(x)=0p(x)=0.

[2]
Write your answer here...
D

quartic polynomial qq has the same first four values as pp, but also q(5)=130q(5)=130. Explain why q(x)p(x)q(x)-p(x) must have factors x1x-1, x2x-2, x3x-3 and x4x-4, and find a possible expression for q(x)q(x).

[2]
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0

Question 59
HL • Paper 3
Hard
Calculator Permitted

A non-zero root transformation is defined as follows. If p(x)=anxn+an1xn1++a0p(x)=a_nx^n+a_{n-1}x^{n-1}+\cdots+a_0 has non-zero roots α1,α2,,αn\alpha_1,\alpha_2,\ldots,\alpha_n, then a new polynomial is formed whose roots are 1α1,1α2,,1αn\frac{1}{\alpha_1},\frac{1}{\alpha_2},\ldots,\frac{1}{\alpha_n}.

A flow diagram showing roots $\alpha_i$ of $p(x)$ mapped to reciprocal roots $1/\alpha_i$ of a new polynomial.
A
I.

Show that a polynomial with roots 1α1,1α2,,1αn\frac{1}{\alpha_1},\frac{1}{\alpha_2},\ldots,\frac{1}{\alpha_n} is proportional to xnp(1x)x^n p\left(\frac{1}{x}\right).

[3]
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II.

Write xnp(1x)x^n p\left(\frac{1}{x}\right) in terms of the coefficients of pp.

[2]
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B

Let p(x)=2x37x2+5x3p(x)=2x^3-7x^2+5x-3. Find a cubic polynomial with integer coefficients whose roots are the reciprocals of the roots of p(x)=0p(x)=0.

[3]
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C
I.

If the roots of p(x)=0p(x)=0 are α\alpha, β\beta and γ\gamma, find 1α+1β+1γ\frac{1}{\alpha}+\frac{1}{\beta}+\frac{1}{\gamma} without solving the cubic.

[2]
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II.

Find the product of the reciprocal roots.

[2]
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D

monic polynomial has non-zero roots and is unchanged by replacing every root by its reciprocal. Deduce a condition on its constant term.

[2]
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0

Question 60
HL • Paper 3
Hard
Calculator Permitted

A monic quartic polynomial PP is required to touch the xx-axis at two distinct points. Let these points be x=ax=a and x=bx=b, where aba\ne b. The graph shown is illustrative only and corresponds to the possible branch a=1a=1, b=5b=5; it does not imply that this is the only possible pair.

Illustrative graph for the possible branch $a=1$, $b=5$; it is not intended to show all polynomials satisfying the conditions.
A
I.

Explain why P(x)P(x) must have the form (xa)2(xb)2(x-a)^2(x-b)^2.

[2]
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II.

Expand P(x)P(x) in terms of s=a+bs=a+b and p=abp=ab.

[2]
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B

particular polynomial of this type has coefficient of x3x^3 equal to 12-12 and constant term 2525. Find all possible values of aa and bb.

[4]
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C
I.

For each polynomial obtained in part (b), find P(x)P(x) in expanded form.

[2]
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II.

For either polynomial obtained in part (b), use your GDC to find the xx-coordinate of the local maximum between the two touching points.

[2]
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D

Prove that, for any distinct real aa and bb, the local maximum between the two touching points occurs at x=a+b2x=\frac{a+b}{2}.

[3]
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0


Modulus & Inequalities

Properties of Functions