Applications of Differentiation (Edexcel IGCSE Further Pure Maths): Exam Questions

Exam code: 4PM1

3 hours22 questions
1a
3 marks

Two numbers x and y are such that 2 x space plus space y space equals space 13

The sum of the squares of 2 x and y is S.

Show that S space equals space 8 x squared space – space 52 x space plus space 169

1b
4 marks

Using calculus, find the value of x for which S is a minimum, justifying that this value of x gives a minimum value for S.

1c
2 marks

Using calculus, find the minimum value of S.

2a
5 marks
Graph of a mathematical function with a wavy curve intersecting the y-axis and dipping below the x-axis at several points, labelled as Figure 1.

Figure 1 shows the curve M with equation space y space equals space x cubed space space – space 13 x – 12

The point P, with x coordinate −2, lies on M and linespace l subscript 1 is the tangent to M at the point P.

Find an equation for space l subscript 1

2b
4 marks

The point Q lies on M and the line l subscript 2 is the tangent to M space at the point Q.

Given that l subscript 1 and l subscript 2 are parallel,

find an equation for l subscript 2

2c
4 marks

The normal to M at P meets l subscript 2 at the point R.

Find the coordinates of R.

3
11 marks
Diagram of a cone with apex B, base ABC, height h cm, slant height l cm, and radius x cm. Note states diagram not accurately drawn.

Figure 2 shows a right circular cone with a base radius of x cm. The slant height of the cone is space l cm and the height of the cone is h cm. The vertex of the cone is B and the points A and C, on the base of the cone, are such that A C is a diameter of the base.

The cone is increasing in size in such a way that the size of the angle A B C is constant at 60 degree and the total surface area of the cone is increasing at a constant rate of 10 cm2 /s.

Find the exact rate of increase of the volume of the cone when x space equals space 6

4
2 marks

straight f left parenthesis x right parenthesis equals space 2 x squared plus 4 x plus 9

Given that straight f left parenthesis x right parenthesis can be written in the form A open parentheses x plus B close parentheses squared plus C , where A comma space B and C are integers,

(i) Hence, or otherwise, find the value of x for which fraction numerator 1 over denominator straight f open parentheses x close parentheses end fractionis a maximum

(ii) find the maximum value of fraction numerator 1 over denominator straight f open parentheses x close parentheses end fraction

5
8 marks

The surface area of a sphere with radius r cm is increasing at a constant rate of 50 pi cm2 /s

Find, in cm3 , the exact volume of the sphere at the instant when the rate of increase of r is 5 over 12 cm/s

6a
6 marks
Graph of a curve on an xy-plane, resembling a parabola opening upwards. The text reads "Diagram NOT accurately drawn." Labelled as Figure 1.

Figure 1 shows a sketch of part of the curve C with equation

y space equals space x squared over 4 space minus space 3 square root of x plus space 8

The point P lies on C and has coordinates left parenthesis 4 comma space a right parenthesis

The line Lis the normal to C at the point P

Show that an equation of L is 5 y space plus space 4 x space minus space 46 space equals 0

6b
6 marks

The finite region R is bounded by the curve C, the line L, the x-axis and the line with equation x space equals space 1

Use calculus to find the exact area of R

7a
4 marks
Geometric diagram with labelled points A, B, C, D, E, and F, including right angles at E and F, arrows indicating x cm and y cm. Diagram not to scale.

Figure 4 shows a solid right triangular prism A B C D E F space

The cross section of the prism is an isosceles triangle.

  • angle D E C space equals space angle A F B space equals space 90 degree

  • A B space equals D C space equals space x cm

  • A D space equals space B C space equals space F E space equals space y spacecm

  • A F space equals space B F space equals space D E space equals space C E

The triangular faces of the prism are vertical and the edges A D comma space B C and F E spaceare horizontal.
The volume of the prism is 3.6 cm3
The total external surface area of the prism is S cm2

Show that S satisfies the equation

S space equals space x squared over 2 plus space fraction numerator 72 open parentheses square root of 2 space plus 1 close parentheses over denominator 5 x end fraction

7b
4 marks

Given that x can vary, use calculus, to find to 3 significant figures, the value of space x for which S is a minimum.

Justify that this value of space x gives a minimum value of S

7c
2 marks

Hence find, to 2 significant figures, the minimum value of S

8a
4 marks
Diagram showing a shape with a quarter-circle and rectangle, labelled with points A to G, and dimensions x cm and r cm. Note: Diagram not accurately drawn.

Figure 2 shows a shape A B C D E O F G

A B C O is a quarter circle with radius r cm
C D E O and space A O F G spaceare congruent rectangles of length r cm and width xcm

The total area of the shape is 100cm2
The perimeter of the shape is P cm

Show that P equals 200 over r plus 2 r

8b
5 marks

Use calculus to find the value of r for which P is a minimum, justifying that this value of r gives a minimum value of P

8c
2 marks

Find the minimum value of P

9
1 mark

straight f open parentheses x close parentheses equals 3 minus 4 x minus 9 x squared

Given that straight f open parentheses x close parenthesescan be expressed in the form A minus B open parentheses x plus C close parentheses squared where A, B and C are positive constants

Hence write down the maximum value of straight f open parentheses x close parentheses

10
5 marks

The height of liquid in a vessel P is h
The volume, V, of the liquid in P is given by V equals 6 h cubed
Liquid is leaking from P at a constant rate of 36 space cm cubed divided by straight s space

Find the exact rate of change, in cm/s, of h when V equals 384 space cm cubed

11
11 marks

A curve C has equation

y equals fraction numerator 5 x minus 2 over denominator 3 x plus 2 end fraction    space space space space space x not equal to 2 over 3

Point A lies on C such that the gradient of C at Ais parallel to the line with equation 4 y minus x minus 7

The normal to C at Aintersects the x-axis at point Dand the y-axis at point E
Given that the x coordinate of A is positive,

find, in its simplified form, the exact length of line D E

Graph with x and y axes, arrows indicating positive directions. The intersection point is marked "O", representing the origin.
12a
4 marks

A solid cuboid has width x cm, length 4x cm and height hcm.
The volume of the cuboid is 75cm3 and the surface area of the cuboid is S space cm squared

Show that S equals 8 x squared plus fraction numerator 375 over denominator 2 x end fraction

12b
5 marks

Given that xcan vary, using calculus,

(i) find to 3 significant figures, the value of x for which S is a minimum,

(ii) justify that this value of x gives a minimum value of S

12c
2 marks

Find, to 3 significant figures, the minimum value of S

13a
7 marks

The equation of a curve is y equals square root of fraction numerator e to the power of 4 x end exponent over denominator 2 x minus 3 end fraction end root

When x is increased to left parenthesis x plus delta x right parenthesis, y increases to left parenthesis y plus delta y right parenthesis where delta x and delta y are small.

Show that delta y almost equal to fraction numerator e to the power of 2 x end exponent left parenthesis 4 x minus 7 right parenthesis over denominator left parenthesis 2 x minus 3 right parenthesis to the power of 3 over 2 end exponent end fraction   delta x

13b
3 marks

The equation of a curve is y equals square root of fraction numerator e to the power of 4 x end exponent over denominator 2 x minus 3 end fraction end root

When x is increased to left parenthesis x plus delta x right parenthesis, y increases to left parenthesis y plus delta y right parenthesis where delta x and delta y are small.

Given that x= 2.5

find an estimate, to 2 significant figures, of the value of delta y when the value of x increases by 0.2%

14
5 marks
Geometric diagram showing two connected polygons with labelled sides and angles, including lengths of 5 cm and angles π/3 radians. Diagram not to scale.

Figure 3 shows a right triangular prism A B C D E F. A cross section A B C of the prism is a triangle in which A B equals A C equals r space cm and angle C A B equals pi over italic 3radians.

The volume of the prism is increasing in such a way that the size of angle C A B and the size of angle D E F remain constant and the length of A E, the length of B F and the length of C D remain constant.
The lengths of A B comma space A C comma space E D and E F are each increasing at a constant rate of 0.2cm / s

Find the exact rate of increase, in cm3 / s, of the volume of the prism when the area of the rectangular face B C D F is 60 cm2

15a
2 marks

straight g left parenthesis x right parenthesis equals 2 x squared plus 1 half x minus 3

Find

(i) the minimum value of straight g open parentheses x close parentheses

(ii) the value of xat which this minimum occurs.

15b
2 marks

straight h left parenthesis x right parenthesis equals 2 x to the power of 6 plus 1 half x cubed minus 3

Hence, or otherwise, write down

(i) the minimum value of straight h open parentheses x close parentheses

(ii) the value of x at which this minimum occurs.

16a
5 marks
Graph with parabola S opening upwards, intersected by line l at points A and P, and shaded region between line, x-axis, and parabola. Axes marked x and y.

Figure 1 shows part of the curve S with equation y equals p x squared plus q x plus r
where p, q and r are constants.

The points A, B and P with coordinates (– 2, 0), (6, 0) and (4, – 6) respectively lie on S

The line l is the normal to S at the point P

Show that an equation of l is 2 y plus x plus 8 equals 0

16b
7 marks
Graph with parabola S and line l intersecting at points A and P. Shaded region is between curve and line. Axes labelled x and y, origin at O.

Figure 1 shows part of the curve S with equation y equals p x squared plus q x plus r
where p, q and r are constants.

The finite region shown shaded in Figure 1 is bounded by S and l

Use algebraic integration to find the exact area of the shaded region.

17
7 marks

The volume of oil in a container is V cm3 when the height of the oil is h cm.
Oil is pouring into the container at a constant rate of 12 cm3 /s.
Given that V equals 3 h cubed

find the exact rate, in cm/s, at which the height of the oil is increasing when V equals 1536 space cm cubed

18a
5 marks

Two numbers x and y are such that 3 x minus y equals 4

S equals 5 x cubed plus y squared
S equals 5 x cubed plus 9 x squared minus 24 x plus 16

Given that x can vary, use calculus to find the value of xfor which S is a minimum, justifying that this value of x gives a minimum value of S

18b
2 marks

Find the minimum value of S

19a
6 marks
Grey sector diagram with angle 0.5 rad at centre D, labelled vertices A to G, dimensions x and y cm, and note: "Diagram NOT accurately drawn."

Figure 1 shows a badge, shown shaded, made from two identical rectangles, A B C D and D E F G, and a sector D C G of a circle with centre D.

Each rectangle measures x cm by y cm.
The radius of the sector is x cm and the angle C D G is 0.5 radians.

The area of the badge is 50 cm2
The perimeter of the badge is P cm.

Show that

P equals 2 x plus 100 over x

Given that x can vary,

use calculus, to find the exact value of x for which P is a minimum.
Justify that this value of x gives a minimum value for P

19b
2 marks

Find the minimum value of P
Give your answer in the form k square root of 2, where k is an integer to be found.

20
7 marks

The equation of a curve is y equals x cubed space sin space x

Find an equation of the tangent to the curve at the point on the curve where x equals 1 half space pi

Give your answer in the form y equals m x plus c

21
7 marks

A cube has edges of length x cm.

The total surface area, A space cm squared , of the cube is increasing at a constant rate of 0.45cm2 /s

Find the rate of increase, in cm3 /s, of the volume of the cube at the instant when the total surface area of the cube is 384cm2

22
4 marks
Graph of the curve \(y = 4 - e^{2x}\) with axes labelled. Points A, O, and B are marked. Note states "Diagram NOT accurately drawn."

Figure 3 shows part of the curve C with equation y equals 4 minus straight e to the power of 2 x end exponent
The curve C crosses the y-axis at the point Aand the x-axis at the point B.

The line l is the normal to C at the point B.

Find an equation for l , giving your answer in the form y equals m x plus c