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Edexcel AL Mathematics: Functions

Section 1: Functions, graphs and transformations


Exercise level 1 solutions
1. (a) (i) The mapping is one-to-many.
(ii) The mapping is not a function.

(b) (i) The mapping is one-to-one.


(ii) The mapping is a function.

(c) (i) The mapping is many-to-many.


(ii) The mapping is not a function.

(d) (i) The mapping is many-to-one.


(ii) The mapping is a function.

2. (a)
A B C

(b) A is many-to-many
B is one-to-one
C isone-to-many

(c) B is a function, A and C are not functions

3. (a) f( x ) = 1− 3x where x  0
The range is f( x )  1.

(b) f( x ) = x 2 where x 

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 1 of 6 integralmaths.org
The range is f( x )  0 .

1
(c) f( x ) = where −1  x  1
1+ x 2
The largest possible value of f( x ) is when x = 0 , where f( x ) = 1 .
The smallest possible value of f( x ) is when x = 1, where f( x ) = 21 .
The range is 1
2
 f( x )  1.

4. (a) f( x )  +
, f( x )  9

(b) f( x )  , − 9  f( x )  21

(c) f( x )  , − 1  f( x )  1

(d) f( x )  , f( x )  0

(e) f( x ) 

(f) f( x )  , 0  f( x )  1

5. (a) y = f( x + 2)

This curve is obtained from the curve y = f ( x) by a translation of 2 units to the left.

The turning point is (-1, 2).

(b) y = f(3x )

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 2 of 6 integralmaths.org
1
This curve is obtained from the curve y = f ( x) by a stretch, scale factor 3
parallel to the x-axis.

The turning point is ( 31 , 2).

(c) y = f( x − 1) + 2

1
This curve is obtained from the curve y = f ( x) by a translation through  .
 2

The turning point is (2, 4).

(d) y = f( − x )

This curve is obtained from the curve y = f ( x) by a reflection in the y-axis.

The turning point is (-1, 2).

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 3 of 6 integralmaths.org
(e) y = −2f( x )

This curve is obtained from the curve y = f ( x) by a reflection in the x-axis and a stretch scale factor 2
parallel to the y-axis.

The turning point is (1, -4).

(f) y = f( 21 x − 1)

This curve is obtained from the curve y = f ( x) by a translation of 1 unit to the right followed by a stretch,
scale factor 2, parallel to the x-axis.

The turning point is (4, 2).

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 4 of 6 integralmaths.org
6. (a)

3
A translation through   maps the curve y = f ( x) to the curve y = f ( x − 3) − 1 .
 −1 

The curve y = x 2 is mapped to the curve


y = ( x − 3)2 − 1
= x2 − 6x + 9 − 1
= x2 − 6x + 8

(b)

A stretch parallel to the x-axis, scale factor 1


2
maps the curve y = f ( x) to the curve y = f (2 x) .

The curve y = x 2 is mapped to the curve


y = (2 x )2
= 4x2

(c)

A reflection in the y-axis maps the curve y = f ( x) to the curve y = f (− x) .

The curve y = x 2 is mapped to the curve


y = ( − x )2
= x2

(d)

A stretch parallel to the y-axis, scale factor 3 maps the curve y = f ( x) to the curve y = 3f ( x) .

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 5 of 6 integralmaths.org
The curve of y = x 2 is mapped to the curve y = 3x 2

(e)

 −2 
  maps the curve y = x to the curve y = ( x + 2)
2 2
A translation through
 0
A reflection in the x-axis maps the curve y = ( x + 2) to the curve y = −( x + 2) .
2 2

y = −( x + 2)2
= −( x 2 + 4 x + 4)
= −x2 − 4x − 4

(f)

A stretch parallel to the y-axis, scale factor 2 maps the curve y = x to the curve y = 2 x .
2 2

1
  maps curve y = 2 x to the curve y = 2( x − 1) 2 + 2
2
A translation through
 
2
A reflection in the y-axis maps the curve y = 2( x − 1) + 2 to the curve y = 2(− x − 1) + 2 .
2 2

y = 2( − x − 1)2 + 2
= 2( x 2 + 2 x + 1) + 2
= 2x 2 + 4 x + 2 + 2
= 2x 2 + 4 x + 4

Edexcel AL Maths: Functions 1 © MEI 22/03/24


Exercise level 1 solutions page 6 of 6 integralmaths.org

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