IB Maths AA HL 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 calculatorMedium7 marks

The graph in Figure 1 shows the straight line ℓ\ell

xyℓ
(a)

Write down the yy-intercept of ℓ\ell and determine its gradient.

[2]
(b)

The line mm is parallel to ℓ\ell and passes through P(2,1)P(2,1) Determine the equation of mm in the form y=mx+cy=mx+c

[2]
(c)

The line nn is perpendicular to ℓ\ell and passes through the point where mm intersects the yy-axis. Determine the equation of nn in the form Ax+By+C=0Ax+By+C=0 where A,B,CA,B,C are integers with no common factor and A>0A>0

[3]

Question 2

Paper 1, no calculatorMedium6 marks

Two analysts model the annual demand for a service in a region. The models predict demand, in thousands of requests per year, tt years from now:

A(t)=8+et/5,B(t)=6et/10,t≥0.A(t)=8+e^{t/5},\qquad B(t)=6e^{t/10},\qquad t\geq 0.

The following values are given, rounded to two decimal places.

tt (years)057810131415
A(t)A(t)9.0010.7212.0612.9515.3921.4624.4428.09
B(t)B(t)6.009.8912.0813.3516.3122.0224.3326.89
(a)

At t=0t=0 state which analyst predicts the greater annual demand.

[1]
(b)

Sketch the two models on the same axes for 0≤t≤150\leq t\leq15 Use your sketch to estimate, to the nearest year, when the forecasts agree.

[2]
(c)

Determine analytically the exact times at which the two forecasts agree. Give your answers in years.

[3]

Question 3

Paper 1, no calculatorMedium6 marks

For real pp consider the equation

x2−2px+p+2=0,x∈R.x^2-2px+p+2=0,\qquad x\in\mathbb R.
(a)

Determine the values of pp for which the equation has (i) two distinct real roots, (ii) two equal real roots, and (iii) no real roots.

[4]
(b)

Hence, when p=3p=3 solve

x2−2px+p+2≤0.x^2-2px+p+2\leq 0.
[2]

Question 4

Paper 2, calculatorMedium7 marks

The function gg is defined by

g(x)=2x+3x−2,x∈R, x≠2.g(x)=\frac{2x+3}{x-2},\qquad x\in\mathbb{R},\ x\ne2.
(a)

State the equations of the vertical and horizontal asymptotes of the graph of gg

[2]
(b)

Sketch the graph of gg showing and labelling its asymptotes and its intercepts with the axes.

[3]
(c)

Determine g−1(x)g^{-1}(x) including its domain, and hence state whether gg is self-inverse.

[2]

Question 5

Paper 2, calculatorMedium6 marks

The function gg is defined by

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

Determine the equations of the vertical and horizontal asymptotes of the graph of gg

[2]
(b)

Verify algebraically that g(g(x))=xg(g(x))=x for x≠1x\ne 1 Hence state the line of symmetry of the graph of gg and describe how reflection in this line maps the asymptotes found in part (a).

[4]

Question 6

Paper 2, calculatorMedium6 marks

A capacitor is discharged from an initial voltage of 10 V. Its voltage VV in volts, tt seconds after discharge is modelled by

V(t)=10at,t≥0,V(t)=10a^t,\qquad t\geq 0,

where 0<a<10<a<1 After 4 seconds, the voltage is 6.4 V.

(a)

Determine the value of aa correct to three significant figures.

[1]
(b)

Let T(V)T(V) give the time, in seconds, at which the voltage is VV Determine T(V)T(V) stating its domain.

[2]
(c)

Hence determine the time at which the model predicts the voltage is 2.5 V. State whether the model predicts that the voltage reaches 0 V at any finite time, and justify your answer.

[3]

Question 7

Paper 1, no calculatorMedium7 marks

Let f(x)=x2−4x+3f(x)=x^2-4x+3 The graph y=f(x)y=f(x) is stretched horizontally by scale factor 22 Let the resulting graph be y=F(x)y=F(x)

(a)

Write down F(x)F(x)

[2]
(b)

The graph y=F(x)y=F(x) is reflected in the xx-axis and then translated upwards by 33 units, giving y=g(x)y=g(x) Determine g(x)g(x) in completed-square form and state the coordinates of its turning point.

[3]
(c)

Instead, starting from y=F(x)y=F(x) translate it upwards by 33 units and then reflect it in the xx-axis, giving y=h(x)y=h(x) Hence, or otherwise, determine whether hh has any xx-intercepts. Give a reason.

[2]

Question 8

Paper 2, calculatorMedium7 marks

Figure 1 shows the graph of y=f(x)y=f(x) for −4≤x≤4-4\leq x\leq 4

-5-4-3-2-112345-4-3-2-10123456xyf(x)

The graph of y=g(x)y=g(x) is obtained from the graph of y=f(x)y=f(x) by reflecting it in the xx-axis, applying a vertical stretch with scale factor 22 and then translating it 11 unit upwards.

(a)

Write down f(−2)f(-2)

[1]
(b)

On the same axes as Figure 1, sketch the graph of y=g(x)y=g(x) Mark the image of the point on y=f(x)y=f(x) for which x=−2x=-2

[2]
(c)

Using Figure 1, determine all values of xx for which g(x)=3g(x)=3

[2]
(d)

For the point (−2,2)(-2,2) on y=f(x)y=f(x) determine its image ordinate if the translation upwards by 11 unit is performed after the reflection but before the vertical stretch. Hence state whether this order of transformations gives the same graph as y=g(x)y=g(x)

[2]

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