Question Bank

Official NZQA past exam questions • AS91578 Differentiation

With video explanations by infinityplusone

15 questions
Achievement
Differentiate y=(lnx)2y = (\ln x)^2.

*You do not need to simplify your answer.*
Achievement
Find the xx-value(s) of any stationary points on the graph of the function f(x)=x2+1xf(x)=\dfrac{x^2+1}{x}.

You must use calculus and show any derivatives that you need to find when solving this problem.
The graph below shows the function y=x+2y = \sqrt{x + 2}, and the normal to the function at the point where
the function intersects the yy-axis.
Loading diagram...
Find the coordinates of point P, the xx-intercept of the normal.

*You must use calculus and show any derivatives that you need to find when solving this problem.*
A curve is defined parametrically by the equations:

x=2+3tx = 2 + 3t and y=3tln(3t1)y = 3t - \ln(3t - 1) where t>13t > \dfrac{1}{3}.

Find the coordinates, (x,y)(x,y), of any point(s) on the curve where the tangent to the curve has a gradient
of 12\dfrac{1}{2}.

*You must use calculus and show any derivatives that you need to find when solving this problem.*
Excellence
If pp is a positive real constant, prove that y=epx2y = e^{px^2} does not have any points of inflection.

You must use calculus and show any derivatives that you need to find when solving this problem.
Achievement
Differentiate f(x)=(5x3)sin(4x)f(x) = (5x - 3)\sin(4x).

*You do not need to simplify your answer.*
Achievement
Find the gradient of the tangent to the curve y=(3x22)3y = (3x^2 - 2)^3 when x=2x = 2.

You must use calculus and show any derivatives that you need to find when solving this problem.
An object is travelling in a straight line. Its displacement, in metres, is given by the formula:

d(t)=t262t3d(t) = \dfrac{t^2 - 6}{2t^3} where t>0t > 0, tt is time in seconds.

Find the time(s) when the object is stationary.

*You must use calculus and show any derivatives that you need to find when solving this problem.*
A rectangle has one vertex at (0,0)(0,0) and the opposite vertex on the curve y=6e10.5xy = 6e^{1-0.5x}, where x>0x > 0, as
shown on the graph below.
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Find the maximum possible area of the rectangle.

*You must use calculus and show any derivatives that you need to find when solving this problem.*

*You do not have to prove that the area you have found is a maximum.*
Excellence
The curve with the equation (y5)2=16(x2)(y-5)^2 = 16(x-2) has a tangent of gradient 1 at point P.
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This tangent intersects the xx and yy axes at points R and S respectively.

Prove that the length RS is 727\sqrt{2}.

*You must use calculus and show any derivatives that you need to find when solving this problem.*
Achievement
Differentiate y=e4xy = e^{4\sqrt{x}}.

You do not need to simplify your answer.
Achievement
The graph below shows the function y=f(x)y = f(x).
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For the function above:
(i) Find the value(s) of xx where f(x)f(x) is not differentiable.

(ii) Find the value(s) of xx for which f(x)=0f'(x) = 0.

(iii) What is the value of limx4f(x)\lim\limits_{x \to -4} f(x)?
(State clearly if the value does not exist.)