IB Maths AI HL AI 5.1 Differentiation 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 2Medium14 marks

A small mass moves vertically on a spring. For t≥0t\geq 0 its displacement yy metres from its equilibrium position is modelled by

y(t)=0.32sin⁡(1.4t+0.30),y(t)=0.32\sin(1.4t+0.30),

where tt is measured in seconds and angles are in radians. This is a model of simple harmonic motion.

(a)

State the amplitude and period of the motion. Calculate the displacement of the mass at t=0t=0 giving your answer to three significant figures.

[3]
(b)

Show that

d2ydt2=−0.6272sin⁡(1.4t+0.30),\frac{d^2y}{dt^2}=-0.6272\sin(1.4t+0.30),

and hence show that

d2ydt2=−1.96y(t).\frac{d^2y}{dt^2}=-1.96y(t).
[3]
(c)

Determine the time of the first stationary point after t=0t=0 Use the second derivative test to classify this point.

[4]
(d)

Using your result from part (b), determine the time of the first point of inflexion after t=0t=0 State the concavity immediately before and after this point, and interpret the point in terms of the mass's motion.

[4]

Question 2

Paper 2Medium13 marks

A landscape designer models the vertical profile of a section of a footpath by

h(x)=0.009x3−0.25x2+1.7x+2.5,0≤x≤20,h(x)=0.009x^3-0.25x^2+1.7x+2.5,\qquad 0\leq x\leq20,

where xx is the horizontal distance, in metres, from the start of the section and h(x)h(x) is the height, in metres, above a reference level.

Consider the point on the profile where x=8x=8

(a)

Calculate the height of the profile at this point.

[2]
(b)

Show that

h′(x)=0.027x2−0.50x+1.7.h'(x)=0.027x^2-0.50x+1.7.
[2]
(c)

Determine the equation of the tangent to the profile at x=8x=8 giving your answer in the form h−h(8)=m(x−8)h-h(8)=m(x-8)

[3]
(d)

Determine the equation of the normal to the profile at x=8x=8 in the same form. Give its gradient to 3 significant figures.

[3]
(e)

Use your GDC to find the coordinates of the other point, different from the point where x=8x=8 at which the tangent in part (c) meets the profile. Give your coordinates to 3 significant figures.

[3]

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