Functions (Edexcel GCSE Maths: Higher): Exam Questions

Exam code: 1MA1

2 hours32 questions
1a
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1 mark

straight f and straight g are functions such that

               straight f open parentheses x close parentheses space equals space 2 over x squared space space space space space space space space space space and space space space space space space straight g open parentheses x close parentheses space equals space 4 x cubed

Find straight f left parenthesis negative 5 right parenthesis

1b
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2 marks

Find fg open parentheses 1 close parentheses

2a2 marks

      straight f open parentheses x close parentheses space equals space 3 x space minus space 2
straight g open parentheses x close parentheses space equals fraction numerator space 10 over denominator x plus 2 end fraction

Express the inverse function straight f to the power of negative 1 end exponent in the form straight f to the power of negative 1 end exponent open parentheses x close parentheses space equals space...

2b2 marks

Find gf left parenthesis x right parenthesis
Simplify your answer.

3a
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1 mark

f is a function such that

straight f open parentheses x close parentheses space equals space fraction numerator 1 over denominator x squared space plus space 1 end fraction

Find straight f open parentheses begin inline style 1 half end style close parentheses

3b2 marks

straight g is a function such that

straight g open parentheses x close parentheses space equals space square root of x minus 1 end root comma space space x greater-than or slanted equal to 1

Find straight f g open parentheses x close parentheses

Give your answer as simply as possible.

4a1 mark

straight f spaceis the function straight f left parenthesis x right parenthesis space equals space 2 x space plus space 5

Find straight f left parenthesis 3 right parenthesis

4b2 marks

Express the inverse function straight f to the power of negative 1 end exponent in the form straight f to the power of negative 1 end exponent open parentheses x close parentheses =

4c1 mark

straight g is the function straight g left parenthesis x right parenthesis space equals space x squared space long dash space 25

Find straight g left parenthesis long dash 3 right parenthesis

4d5 marks

i) Find gf left parenthesis x right parenthesis
Give your answer as simply as possible.

[3]

ii) Solve gf left parenthesis x right parenthesis space equals space 0

[2]

5a1 mark

The functions straight f and straight g are defined as

straight f open parentheses x close parentheses space equals space 1 half x space plus 4
straight g open parentheses x close parentheses space equals space fraction numerator 2 x over denominator x plus 1 end fraction

Work out straight f left parenthesis 6 right parenthesis

5b
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2 marks

Work out  fg left parenthesis long dash 3 right parenthesis

5c2 marks

straight g left parenthesis a right parenthesis space equals space minus 2

Work out the value of a.

5d3 marks

Express the inverse function straight f to the power of negative 1 end exponent in the form straight f to the power of negative 1 end exponent left parenthesis x right parenthesis = ...

6a
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1 mark

f is the function such that  f(x) = 2x - 5
g is the function such that g(x) = x2 - 10

Find f (4)

6b
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2 marks

Find fg(-4)

6c2 marks

Express the inverse function f-1 in the form f-1 (x) = ...

6d
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4 marks

Solve gf (x) = -1

7a
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1 mark

The functions straight f and straight g are such that

 space straight f left parenthesis x right parenthesis space equals space 3 left parenthesis x long dash space 4 right parenthesis space and space straight g left parenthesis x right parenthesis space equals x over 5 plus 1

Find the value of straight f open parentheses 10 close parentheses

7b2 marks

Find  straight g to the power of negative 1 end exponent open parentheses x close parentheses

7c2 marks

Show that ff left parenthesis x right parenthesis space equals space 9 x space long dash space 48

81 mark

straight g open parentheses x close parentheses equals 2 x and  straight h open parentheses x close parentheses equals fraction numerator x minus 1 over denominator 2 end fraction

Choose the expression for hg left parenthesis x right parenthesis

  • fraction numerator 2 x squared minus x over denominator 2 end fraction

  • fraction numerator 2 x minus 1 over denominator 2 end fraction

  • x squared minus x

  • x minus 1

91 mark

straight f left parenthesis x right parenthesis space equals space 3 x

Choose the expression forspace straight f to the power of negative 1 end exponent left parenthesis x right parenthesis

  • negative 3 x

  • 3 over x

  • fraction numerator 1 over denominator 3 x end fraction

  • x over 3

10a
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2 marks

A function is represented by the following function machine.

q8a-paper4-spec2015-ocr-gcse-maths

A number is input into the machine.
The output is used as a new input.
The second output is 11.

Work out the number that was the first input.

10b
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3 marks

A number is input into the machine.
The output given is the same number.

Work out the number.

13 marks

straight f left parenthesis x right parenthesis space equals space 3 x squared long dash 2 x long dash 8

Express space straight f left parenthesis x space plus space 2 right parenthesis space in the form a x squared space plus space b x

2a3 marks

The functions straight f and straight g are such that straight f left parenthesis x right parenthesis space equals space x space plus space 3     and       straight g open parentheses x close parentheses space equals space fraction numerator 1 over denominator x minus 2 end fraction

Find space fg left parenthesis x right parenthesis space
Give your answer as a single algebraic fraction expressed as simply as possible.

2b3 marks

Express the inverse function straight g to the power of negative 1 end exponent in the form straight g to the power of negative 1 end exponent open parentheses x close parentheses space equals space...

3a2 marks

The function straight f is such that

straight f left parenthesis x right parenthesis space equals space 4 x long dash space 1

Find straight f to the power of negative 1 end exponent left parenthesis x right parenthesis

3b2 marks

The function straight g is such that

straight g left parenthesis x right parenthesis space equals space k x squared where k is a constant.

Given that fg left parenthesis 2 right parenthesis space equals space 12

work out the value of k

4a2 marks

The functions straight f and straight g are such that

straight f open parentheses x close parentheses space equals space 3 x space minus 1 space space space space and space space space space space space space straight g open parentheses x close parentheses space equals space x squared plus 4

Find straight f to the power of negative 1 end exponent left parenthesis x right parenthesis

4b5 marks

Given that fg left parenthesis x right parenthesis space equals space 2 gf left parenthesis x right parenthesis,

show that 15 x to the power of 2 space end exponent minus space 12 x long dash 1 equals space 0

5
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4 marks

straight f open parentheses x close parentheses equals 2 x minus 3 and straight g open parentheses x close parentheses equals x squared

Show that  straight f to the power of negative 1 end exponent open parentheses 55 close parentheses equals straight f g open parentheses 4 close parentheses

62 marks

straight f left parenthesis x right parenthesis space equals space x over 3 plus space 4  for all values of x.

straight g left parenthesis x right parenthesis space equals space 6 x squared space plus space 3 for all values of x.

Work out fg left parenthesis x right parenthesis.

Give your answer in the form a x squared space plus space b   where a and b are integers.

7
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3 marks

table row cell straight f open parentheses x close parentheses end cell equals cell c x plus d end cell row cell straight f open parentheses 4 close parentheses end cell equals 7 row cell straight f open parentheses 10 close parentheses end cell equals 22 end table

Work out the values of c and d.

c space equals.........................     

d space equals.........................     

8
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2 marks

straight f left parenthesis x right parenthesis space equals space 3 x squared space – space 4 x space plus space 8 for all values of x

Jenny says,

“f(10) must equal 2 × f(5), because 10 is 2 × 5”

Is Jenny correct?
Show working to support your answer.

93 marks

straight g left parenthesis x right parenthesis space equals space 16 space – space x space space space space straight h left parenthesis x right parenthesis space equals space x cubed

Solve    gh open parentheses x close parentheses equals 24

103 marks

straight f left parenthesis x right parenthesis space equals space fraction numerator x over denominator x plus 2 end fraction space space space space space space space space space space space space space space space space space straight g left parenthesis x right parenthesis space equals space x squared space – space 2

Work out fg left parenthesis x right parenthesis

Give your answer in the form    a space plus space b x to the power of n    where a comma space b and n are integers.

114 marks

space straight f left parenthesis x right parenthesis space equals space fraction numerator 2 x space plus space 3 over denominator x minus 4 end fraction

Work out straight f to the power of – 1 end exponent space left parenthesis x right parenthesis

12
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3 marks

straight g open parentheses x close parentheses space equals space 3 x plus 7

Solve  straight g to the power of – 1 end exponent space left parenthesis x right parenthesis space equals space 2 x

x = ....................

13
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3 marks

A function machine is shown below.

q8b-paper4-spec2015-ocr-gcse-maths

If the Input is 3, the Output is 5.
If the Input is 7, the Output is 25.

Use this information to fill in the two boxes.

1a2 marks

Show that fraction numerator x squared space plus space 3 x over denominator 2 x squared space plus space 5 x minus 3 end fraction can be written as  fraction numerator x over denominator k x space minus 1 end fraction

State the value of k.

1b3 marks

straight f left parenthesis x right parenthesis space equals space fraction numerator x over denominator 2 x space minus 1 end fraction

Find the inverse function straight f space to the power of negative 1 end exponent  in the form straight f space to the power of negative 1 end exponent open parentheses x close parentheses space equals space.......
Show your working clearly.

2
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5 marks

The functions straight f and straight g are such that

straight f left parenthesis x right parenthesis space equals space 5 x space plus space 3 space space space space straight g left parenthesis x right parenthesis space equals space a x space plus space b where a and b are constants.

straight g left parenthesis 3 right parenthesis space equals 20 space space space space space space space and space space space space space space straight f to the power of negative 1 end exponent left parenthesis 33 right parenthesis equals space straight g left parenthesis 1 right parenthesis

Find the value of a and the value of b.

34 marks

straight f open parentheses x close parentheses equals 1 half x      straight g open parentheses x close parentheses equals x minus x squared

Solve  straight f to the power of – 1 end exponent left parenthesis x right parenthesis space equals space gf left parenthesis x right parenthesis

4
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5 marks

straight f open parentheses x close parentheses equals fraction numerator 2 x over denominator 5 end fraction minus 1

Work out the value of  straight f to the power of – 1 end exponent left parenthesis 3 right parenthesis space plus space straight f left parenthesis – 0.5 right parenthesis

53 marks

straight f open parentheses x close parentheses space equals space 5 minus x  and     straight g open parentheses x close parentheses space equals space 3 x plus 7

Simplify straight f left parenthesis 2 x right parenthesis space plus space straight g left parenthesis x space – space 1 right parenthesis

6
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2 marks

straight h left parenthesis x right parenthesis space equals space cube root of x   for all values of x

On the grid, draw the graph of the inverse function y equals straight h to the power of negative 1 end exponent open parentheses x close parentheses  for  negative 2 less-than or slanted equal to x less-than or slanted equal to 2

q27a-paper2h-june2017-aqa-gcse-maths
7
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2 marks

For all values of x

straight f left parenthesis x right parenthesis space equals space sin space x
straight g left parenthesis x right parenthesis space equals space x space plus space 90

On the grid, draw the graph of the composite function  y equals fg open parentheses x close parentheses  for  0 degree space less-than or slanted equal to space x space less-than or slanted equal to space 360 degree

q27b-paper2h-june2017-aqa-gcse-maths
8
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3 marks

straight f left parenthesis x right parenthesis space equals space 2 x space plus space c

straight g left parenthesis x right parenthesis space equals space c x space plus space 5

straight f g left parenthesis x right parenthesis space equals space 6 x space plus space d

c and d are constants.

Work out the value of d space.

9
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4 marks

Here are two function machines, A and B.

q19-paper3h-specimen2015-aqa-gcse-maths

Both machines have the same input.

Work out the range of input values for which the output of A is less than the output of B.