Relations and Function Notation

136.
The diagram shows a region enclosed by three straight lines A, B and C.
The equation of line A is 2 y + 2 = x .
Region enclosed by three straight lines
(a) Show that the equation of the line C is 2 y = 3 x + 6 .
(a) ......................... [3]
(b) Write down three inequalities which satisfy the shaded region.
(b) ......................... [3]
(c) For a point (x, y) in the shaded region, find the minimum value of x − y.
(c) ......................... [2]
Paper 2
137.
In the diagram, the coordinates of B and D are (2, 3) and (0, −4½).
OB is parallel to DC.
Parallel lines OB and DC
(a) Show that the point C is (3, 0).
(a) ......................... [2]
(b) Find the equation of line CD.
(b) ......................... [2]
(c) Given that the length of BC is r , find the value of r.
(c) r = ......................... [2]
Paper 2
141.
The diagram shows a straight line AB of gradient 3 4 .
Straight line AB with gradient -3/4
Find:
(a) The coordinates of A,
(a) A = (......................... , .........................) [2]
(b) The distance AB,
(b) ......................... [2]
(c) The equation of a line parallel to AB passing through (4, 2).
(c) ......................... [2]
Paper 2
142.
Points (x, 4) and (5, 1) are 5 units apart.
Find x.
x = ......................... or x = ......................... [3]
Paper 2
143.
f ( x ) = 2 x 3 and g ( x ) = 4 x .
Find:
(a) g ( 0.5 )
(a) ......................... [1]
(b) g f ( x )
(b) ......................... [1]
Paper 2
144.
It is given that 5 3 = 1.7 , 50 3 = 3.7 , and 500 3 = 7.9 .
Find the value of 0.005 3 .
......................... [2]
Paper 2
146.
Line graph on a grid
(a) Find the equation of the line l.
(a) y = ......................... [2]
(b) Draw the line on the same grid that is parallel to line l passing through the point (1, 1).
(b) See diagram [1]
Paper 2
74.
The diagram shows the graph of f ( x ) = x 2 + 7 x + 8 and g ( x ) = 3 x + 24 .
f(x) cuts the x-axis at A and B.
f(x) and g(x) intersect at B and D.
F is a point on f(x) and E is a point on g(x).
EF is parallel to the y-axis.
Graphs of f(x) and g(x)
(a) Write the coordinates of point C.
(........................., .........................) [1]
(b) Determine the coordinates of A and B.
A = (........................., .........................) B = (........................., .........................) [4]
(c) Find the x-coordinate of point D.
x = ......................... [3]
(d) Determine EF in terms of x.
EF = ......................... [2]
Paper 4
75.
f ( x ) = 3 x + 2 2
Find:
(i) 1 2 f ( x ) ,
......................... [1]
(ii) f(2).
f(2) = ......................... [2]
Paper 4
77.
(a) Complete the table of values for y = 2 x ; x 0 .

x -5 -4 -2 -1 -0.5 -0.25 0.25 0.5 1 2 4 5
y -0.4 -1 -2 -4 4 2 1 0.4

(b) Explain why the value of x cannot be zero.
......................... [1]
(c) On the grid, draw the graph of y = 2 x for 5 x 5 .
-5 -4 -3 -2 -1 0 1 2 3 4 5 8 7 6 5 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
[4]
(d) On the same axes, draw the graph of y = 2 x for 5 x 5 .
[2]
(e) Use your graphs to solve 2 x 2 x = 0 .
x = ......................... or x = ......................... [2]
(f) By drawing a suitable tangent, estimate the gradient of the graph at x = 2.
Gradient = ......................... [2]
Paper 4
78.
(a) f ( x ) = 1 x
Find:
(i) f(3),
f(3) = ......................... [1]
(ii) f ( k 4 ) , in terms of k,
......................... [1]
(iii) k if, f ( 2 k 4 ) = 2 ,
k = ......................... [3]
(iv) f f ( 8 k k 5 ) , in terms of k,
......................... [1]
(b) Another function g(x) is such that:
g(192) = 850, and g−1(x) exists.
Find g−1g(192).
......................... [1]
(c) Simplify f(x)f(x) − ff(x).
Give your answer as a single fraction, in terms of x.
......................... [2]
Paper 4
79.
f ( x ) = 3 2 x + 2
(a) Find:
(i) f(−1),
f(−1) = ......................... [1]
(ii) f−1(x).
f−1(x) = ......................... [2]
(b) Find gf(x) in its simplest form.
gf(x) = ......................... [3]
(c) Solve the equation.
f ( x 2 + 1 ) = 17
x = ......................... or x = ......................... [3]
Paper 4
80.
The table shows some values of x and y for the function y = 2 ( 3 + x ) .

x -5 -4 -3 -2 -1 0 1
y 0.3 1 2 4 8 16

(a) Complete the table.
See table [1]
(b) On the grid provided plot the points in the table and join them with a smooth curve.
x y -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 -1 -2 -3
See diagram [3]
(c) Use your graph to find the value of x when y = 5.
x = ......................... [1]
(d) By drawing a tangent, find the gradient of the curve at x = −1.5.
Gradient = ......................... [3]
(e) On the same axes draw the graph of y = 3x + 9.
See diagram [2]
(f) Use your graphs to find the solution to the equations 2 ( 3 + x ) 3 x 3 = 6 .
x = ......................... [2]
Paper 4
82.
f ( x ) = 2 x 2 1 , g ( x ) = 5 x + 2 , h ( x ) = x 4 3
(a) Evaluate f(2).
f(2) = ......................... [1]
(b) Find the positive value of x for which f(x) = 17.
x = ......................... [3]
(c) Find g2(x).
g2(x) = ......................... [2]
(d) Work out g−1(x).
g−1(x) = ......................... [2]
(e) Given that f(x) = h(x) reduces to A x 2 + B x 7 = 0 , find the value of A and B.
A = ......................... B = ......................... [3]
Paper 4
83.
The diagram shows the parabola, f(x), and the straight line, g(x).
Points A, B, C and D are the intercepts on the axes.
E is the point of intersection of the two graphs.
Parabola and straight line
(a) D is the image of B after B has been translated two units to the right.
Write the coordinates of point D.
D = (........................., .........................) [1]
(b) Find the equation of the straight line through C and D.
Give your answer in the form y = mx + c.
y = ......................... [2]
(c) Find the equation of the parabola in the form y = a x 2 + b x + c .
y = ......................... [4]
(d) Work out the coordinates of point E.
E = (........................., .........................) [4]
(e) Write down the values of x for which f(x) ≥ g(x).
......................... [2]
Paper 4
85.
f ( x ) = 2 x and g ( x ) = 2 x + 3
(a) Find:
(i) f(3),
f(3) = ......................... [1]
(ii) g−1(x),
g−1(x) = ......................... [2]
(iii) gf(x), in its simplest form.
gf(x) = ......................... [2]
(b) Solve f ( x ) = 8 x 1 .
x = ......................... [3]
(c) Given that gh(x) = 6x − 1, find h(x).
h(x) = ......................... [3]
Paper 4
86.
The table shows some values of y = x 2 + x 2 .

x -3.5 -2 -1.5 -1 0 0.5 1 1.5 2
y 6.75 0 -1.25 -2 -2 p 0 q 4

(a) Calculate the value of p and the value of q.
p = ......................... q = ......................... [2]
(b) On the grid, draw the graph of y = x 2 + x 2 for 3.5 x 2 .
-5 -4 -3 -2 -1 0 1 2 3 4 5 8 7 6 5 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8
See diagram [4]
(c) Write the equation of the line of symmetry of the graph.
......................... [1]
(d) (i) On the same grid, draw the graph of x + y = 2.
(ii) Use your graphs to solve the equation x 2 + 2 x = 4 .
x = ......................... or x = ......................... [2]
Paper 4
90.
The functions f and g are defined as follows:
f : x ( 2 x 1 ) x 2 2 x 3 1 x 3 , x > 3 , and g : x 2 x 3 .
(a) Show that f ( x ) = 1 x + 1 .
......................... [3]
(b) Find:
(i) f−1(x),
f−1(x) = ......................... [2]
(ii) g−1(x),
g−1(x) = ......................... [2]
(iii) fg(x),
fg(x) = ......................... [2]
(iv) (fg)−1(x).
(fg)−1(x) = ......................... [2]
(c) Solve fg(x) = 1 8 .
x = ......................... [2]
(d) Show that ( f g ) 1 ( x ) = g 1 f 1 ( x ) .
......................... [3]
Paper 4
91.
It is given that f and g are functions of x.
f ( x ) = 1 x + 2 + 3 and g ( x ) = 3 2 x
(a) Evaluate:
(i) g(−7)
g(−7) = ......................... [2]
(ii) fg(3)
fg(3) = ......................... [3]
(b) Find the value of x for which f(x) = 0.
x = ......................... [2]
(c) Express in terms of x:
(i) g−1(x),
g−1(x) = ......................... [2]
(ii) g(x)g(x).
g(x)g(x) = ......................... [2]
(d) Given that p is another function of x such that p(x) = xn.
Find n if p(x) = p−1(x).
n = ......................... [2]
Paper 4
92.
(a) Complete the table of values for y = 1 3 x 3 + x 2 2 x .

x -4 -3 -2 -1 0 1 2 3
y 2.7 5.3 2.7 0 -0.7 12

(b) On the grid, draw the graph of y = 1 3 x 3 + x 2 2 x for 4 x 3 .
x y -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 -1 -2 -3
See table and diagram [6]
(c) Use the graph to solve the equation y = 1 3 x 3 + x 2 2 x = 4 .
x = ......................... or x = ......................... or x = ......................... [3]
(d) The equation y = 1 3 x 3 + x 2 7 = 5 x can be solved by drawing a straight line on the grid.
Find the equation of this straight line in the form of y = mx + c.
y = ......................... [2]
Paper 4
93.
The table shows some values of y = x ( x + 2 ) ( x 1 ) for 2.5 x 1.5 .

x -2.5 -2 -1.5 -1 0 1 1.5
y -4 0 2 0 0

(a) Complete the table.
(b) On the grid, draw the graph of y = x ( x + 2 ) ( x 1 ) for 2.5 x 1.5 .
-4 -3 -2 -1 0 1 2 3 5 4 3 2 1 -1 -2 -3 -4 x y
See table and diagram [5]
(c) Use the graph to find the values of x when y = 0.
x = ......................... or x = ......................... or x = ......................... [3]
(d) By drawing a suitable straight line, find one of the solutions for y = x 3 + x 2 x 1 .
x = ......................... [2]
Paper 4
95.
(a) f(x) = 6x − x2

(i) Complete the table for f(x).

x 0 1 2 3 4 5 6
f(x) 0 9 0
(a)(i) See table [2]
(ii) On the grid, draw the graph of y = f(x) for 0 ≤ x ≤ 6.
-2 -1 0 1 2 3 4 5 6 7 10 9 8 7 6 5 4 3 2 1 -1 -2 x y
(a)(ii) See diagram [3]
(iii) Use your graph to solve the equation f(x) = 6.
x = ......................... or x = ......................... [2]
(iv) By drawing a tangent at the point where x = 4, estimate the gradient of the graph of y = f(x) when x = 4.
Gradient = ......................... [3]
(b) g(x) = 2x

(i) Complete the table for g(x).

x 0 1 2 3 3.3
g(x) 8 9.8
(b)(i) See table [2]
(ii) On the same grid opposite, draw the graph of y = g(x) for 0 ≤ x ≤ 3.3.
(b)(ii) See diagram [3]
(c) Use your graphs to find x when f(x) = g(x).
x = ......................... or x = ......................... [2]
Paper 4
97.
The table shows values of the function y = 1 3 x 3 x + 4 .
X -3 -2.5 -2 -1.5 -1 0 1.5 2 2.5 3
y -2 3.3 4.0 4.7 6.7 10

(a) Complete the table.
(b) On the grid, draw the graph of y = 1 3 x 3 x + 4 for 3 x 3 .
-3 -2 -1 0 1 2 3 11 10 9 8 7 6 5 4 3 2 1 -1 -2 -3 x y
See table and diagram [7]
(c) Use your graph to solve the equation y = 1 3 x 3 x = 0.2 .
x = ......................... or x = ......................... or x = ......................... [3]
(d) By drawing a suitable straight line on the same grid, solve the equation 1 3 x 3 x = x + 4 .
x = ......................... or x = ......................... or x = ......................... [4]
Paper 4
98.
The functions, f and g, are defined by
f ( x ) = x 3 + 1 and g ( x ) = 2 x 1 .
(a) Calculate g(−3)
g(−3) = ......................... [1]
(b) Find, in its simplest form:
(i) f−1(x),
f−1(x) = ......................... [2]
(ii) fg(x),
fg(x) = ......................... [2]
(iii) (fg)−1(x).
(fg)−1(x) = ......................... [2]
(c) Find g 1 ( 2 1 2 ) .
......................... [3]
(d) Find the value of x for which f(x) = 5.
x = ......................... [4]
Paper 4