IB Maths AA SL Topic 2: Functions questions

Exam-style questions in the shape of Paper 1 and Paper 2, with full markschemes. Read the markscheme, or type, photograph or draw your answer and get it marked.

Question 1

Paper 1, no calculatorMedium6 marks

The function ff is defined by

f(x)=(x−2)2+1,x≥2.f(x)=(x-2)^2+1,\qquad x\geq 2.
(a)

Explain why ff has an inverse function.

[1]
(b)

Find f−1(x)f^{-1}(x) stating its domain.

[3]
(c)

Using your answer to (b), determine (f−1∘f)(5)(f^{-1}\circ f)(5) showing the value of f(5)f(5)

[2]

Question 2

Paper 2, calculatorMedium7 marks

A quadratic function ff has xx-intercepts (−2,0)(-2,0) and (6,0)(6,0) Its graph passes through (0,24)(0,24)

(a)

Determine f(x)f(x) in factored form.

[3]
(b)

Hence write f(x)f(x) in vertex form and state the equation of its axis of symmetry.

[4]

Question 3

Paper 1, no calculatorMedium7 marks

For real kk let qk(x)=x2−4x+kq_k(x)=x^2-4x+k where x∈Rx\in\mathbb R

(a)

Solve q3(x)=0q_3(x)=0

[2]
(b)

Hence solve q3(x)≤0q_3(x)\leq 0

[2]
(c)

Determine the values of kk for which qk(x)=0q_k(x)=0 has: (i) two distinct real roots; (ii) two equal real roots; (iii) no real roots.

[3]

Question 4

Paper 2, calculatorMedium7 marks

For real tt let qtq_t be the quadratic function defined by

qt(x)=x2+(t−4)x+2t+1.q_t(x)=x^2+(t-4)x+2t+1.
(a)

Determine the discriminant, Δt\Delta_t of qt(x)q_t(x)

[2]
(b)

Given that 0≤t≤100\leq t\leq 10 determine the set of values of tt for which qt(x)=0q_t(x)=0 has two distinct real roots.

[3]
(c)

Hence, identify the integer value of tt in this set and solve qt(x)≤0q_t(x)\leq 0 for x∈Rx\in\mathbb{R}

[2]

Question 5

Paper 2, calculatorMedium6 marks

For real kk consider the equation

(k+1)x2−4x+1=0.(k+1)x^2-4x+1=0.
(a)

Determine the values of kk for which the equation has two distinct real roots, two equal real roots, or no real roots. State separately what happens when the equation is not quadratic.

[3]
(b)

Hence, when k=2k=2 solve the inequality

(k+1)x2−4x+1≤0.(k+1)x^2-4x+1\leq 0.
[3]

Question 6

Paper 2, calculatorMedium5 marks

Let f(x)=1xf(x)=\dfrac{1}{x} x≠0x\ne 0 and define

g(x)=3+2f(x−1)=3x−1x−1,x≠1.g(x)=3+2f(x-1)=\frac{3x-1}{x-1},\qquad x\ne 1.
(a)

State the inverse function of ff

[1]
(b)

Hence determine g−1(x)g^{-1}(x) and state the equations of its vertical and horizontal asymptotes.

[4]

Question 7

Paper 1, no calculatorMedium5 marks

The graph of the function rr is shown in Figure 1. It is known that

r(x)=ax+bx+d,x≠−d,r(x)=\frac{ax+b}{x+d}, \qquad x\ne-d,

where a,b,d∈Ra,b,d\in\mathbb R

-4-3-2-1012344321-1-2-3-4(1,1)x=0y=0xy
(a)

Determine the values of aa bb and dd

[3]
(b)

Hence, show that rr is self-inverse, stating the domain of r−1r^{-1}

[2]

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