Exponential & Logarithms (Edexcel A Level Maths: Pure): Exam Questions

2 hours44 questions
1
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3 marks

Find the value of

(i) 3 cubed

(ii) 4 to the power of negative 2 end exponent

(iii) 9 to the power of 0.5 end exponent

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23 marks

Sketch the curve with equation

y equals a to the power of x space space space space space space space space a greater than 1

showing clearly any points of intersection with the coordinate axes.

State whether the graph shows exponential growth or exponential decay.

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33 marks

State whether the following models represent exponential growth or exponential decay:

(i) y equals 3 to the power of negative 2 x end exponent

(ii) y equals 20 open parentheses 2 close parentheses to the power of x

(iii) y equals 30 a to the power of negative x end exponent where a greater than 1

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4
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3 marks

Write down the value(s) of a in the following:

(i) 3 to the power of a equals 27

(ii) a to the power of begin inline style 1 third end style end exponent equals 5

(iii) 4 a squared equals 64

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5
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3 marks

Write down the value of a in the following:

(i) log subscript 3 a equals 4

(ii) log subscript a space end subscript 216 equals 3

(iii) log subscript 2 space end subscript 128 equals a

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6
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1 mark

Solve the equation

2 to the power of x equals 16

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7a
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2 marks

Solve the equation

x squared minus 12 x plus 27 equals 0

7b
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3 marks

Hence solve the equation

open parentheses 3 to the power of x close parentheses squared minus 12 open parentheses 3 to the power of x close parentheses plus 27 equals 0

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8
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2 marks

Solve the equation

2 log subscript 3 space 9 equals 5 x minus 6

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92 marks

Sketch the curve with equation

y equals straight e to the power of x

showing clearly any points of intersection with the coordinate axes.

On your sketch, state the equation of the asymptote.

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10
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2 marks

A curve has the equation y equals straight e to the power of 2 x end exponent

(i) Write down an expression for fraction numerator straight d y over denominator straight d x end fraction

(ii) Find the gradient of the point on the curve where x equals 0

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11
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2 marks

Find the values of

(i) 5 space log subscript 3 space 7

(ii) 2 space log subscript 2 space 3plus 3 space log subscript 3 space 2

giving your answers to 4 significant figures.

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12
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3 marks

Solve the equation

straight e to the power of 2 x end exponent minus 16 equals 0

giving your answer in the form

a ln space a 

where a is an integer.

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13
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4 marks

Write down the value of a in the following:

(i) log subscript a space 8 equals 3

(ii) log space a equals 2

(iii) ln space straight e cubed equals a

(iv) log subscript 5 space a equals 1

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141 mark

The function straight f open parentheses x close parentheses is defined by

straight f open parentheses x close parentheses equals 3 straight e to the power of 2 x end exponent space space space space space space space space x element of straight real numbers

Find an expression for straight f open parentheses italic 2 x close parentheses.

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151 mark

The function straight f open parentheses x close parentheses is defined by

straight f open parentheses x close parentheses equals 5 straight e to the power of 3 x end exponent space space space space space space space space x element of straight real numbers

Find an expression for straight f open parentheses 4 x close parentheses.

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1a2 marks

Sketch the curve with equation

y equals 4 to the power of x

stating any points of intersection with the coordinate axes.

1b
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2 marks

Solve

4 to the power of x equals 100

giving your answer to 2 decimal places.

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23 marks

On the same set of coordinate axes, sketch the curves

y equals 2 to the power of x

and

y equals 3 to the power of x

Label clearly

  • any points where the curves meet the coordinate axes

  • the equation(s) of any asymptotes

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3a3 marks

Sketch the curve

y equals 1 over 2 to the power of x

State whether the graph shows exponential growth or exponential decay.

3b
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1 mark

Find the exact value of y spacewhen x equals 3.

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4
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2 marks

Solve the equation

3 space log subscript 2 space 4 plus 3 x equals 5 space log subscript 6 space 216

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53 marks

Use algebra to solve

2 to the power of 2 x end exponent minus 24 open parentheses 2 to the power of x close parentheses plus 128 equals 0

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6a3 marks

On the same set of coordinate axes, sketch the curves

y equals straight e to the power of x

and

y equals straight e to the power of negative x end exponent

Label clearly

  • any points where the curves meet the coordinate axes

  • the equation(s) of any asymptotes

6b1 mark

Write down the gradient of the curve

y equals straight e to the power of x

at the point open parentheses 0 comma 1 close parentheses.

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7a1 mark

Given that

y equals straight e to the power of 4 x end exponent

write down an expression for fraction numerator straight d y over denominator straight d x end fraction

7b1 mark

Given that

y equals 2 straight e to the power of 2 x end exponent

write down an expression for fraction numerator straight d y over denominator straight d x end fraction

7c
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3 marks

A curve has equation

y equals 3 straight e to the power of negative 2 x end exponent

Find the gradient of the point on the curve where x equals 3.

Give your answer in the form

p straight e to the power of q

where p and q are integers to be found.

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8a
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2 marks

(i) Write down the gradient function of the curve y equals straight e to the power of negative 3 x end exponent

(ii) Find the gradient of the curve y equals straight e to the power of negative 3 x end exponent at the point where x equals 0

8b
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2 marks

(i) write down the exact gradient of the point on the curve y equals straight e to the power of negative 3 x end exponent where x equals 2

(ii) Find the x-coordinate of the point on the curve y equals straight e to the power of negative 3 x end exponent which has a gradient of negative 3 straight e to the power of negative 12 end exponent

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9a3 marks

The function straight f open parentheses x close parentheses is defined by

straight f open parentheses x close parentheses equals 2 straight e to the power of 3 x end exponent space space space space space space space space x element of straight real numbers

(i) Write down the function straight f open parentheses negative x close parentheses.

(ii) On the same set of coordinate axes, sketch the curves of y equals straight f open parentheses x close parentheses and y equals straight f open parentheses negative x close parentheses.

Label any points where the graphs intersect the coordinate axes.

9b1 mark

A different function is given by

straight g open parentheses x close parentheses equals negative 2 straight e to the power of 3 x end exponent

State the single graph transformation that maps the curve y equals straight f open parentheses x close parentheses to the curve y equals straight g open parentheses x close parentheses.

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10
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3 marks

Solve

straight e to the power of 2 x end exponent minus 8 straight e to the power of x plus 15 equals 0

giving your answer(s) to 3 significant figures.

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11a3 marks

On the same set of coordinate axes, sketch the curves

y equals 4 to the power of x

and

y equals 5 to the power of x

Label clearly

  • any points where the curves meet the coordinate axes

  • the equation(s) of any asymptotes

11b1 mark

Write down an equation of the curve that is a reflection of y equals 4 to the power of x in the y-axis.

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12a3 marks

(i) Sketch the curve with equation y equals 0.4 to the power of x

(ii) State whether the curve represents exponential growth or exponential decay.

12b1 mark

Find the value of x when y equals 0.064.

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13a
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1 mark

Find the value of

log space 1000 plus log space 10000

13b
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1 mark

Solve

6 to the power of log subscript 6 space a end exponent equals 36

13c
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2 marks

Find the value of

fraction numerator 2 log subscript 4 space 64 plus 3 to the power of log subscript 2 space 8 end exponent minus log subscript 5 space 5 over denominator log space 100 end fraction

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14a3 marks

Sketch the curve with equation

y equals 12 straight e to the power of negative x end exponent space space space space space space space space space x greater or equal than 0

stating any points of intersection with the coordinate axes.

Write down the equations of any asymptotes.

14b1 mark

Find the gradient of the point on the curve y equals 12 straight e to the power of negative x end exponent where x equals 0.

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15a
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2 marks

Solve

2 space log space 1000 equals x space log subscript 16 space 4

15b
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2 marks

Solve

3 space log subscript 4 space x equals log subscript 4 space x plus 3 space log subscript 5 space 25

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16a3 marks

On the same set of coordinate axes, sketch the curves

y equals 0.3 to the power of x

and

y equals 0.5 to the power of x

Label clearly

  • any points where the curves meet the coordinate axes

  • the equation(s) of any asymptotes

16b1 mark

Write down an equation of the curve that is a reflection of y equals 0.5 to the power of x in the y-axis.

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17a3 marks

Sketch the curve

y equals 0.2 to the power of negative x end exponent

State

  • the equation of the asymptote

  • whether the graph shows exponential growth or exponential decay.

17b1 mark

Find the value of x when y equals 625.

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18a3 marks

Sketch the curve with equation

y equals 4 straight e to the power of x space space space space space space space space space x greater or equal than 0

stating any points of intersection with the coordinate axes.

Write down the equations of any asymptotes.

18b
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2 marks

Find the gradient of the point on the curve y equals 4 straight e to the power of x where x equals 3.

Give your answer correct to 3 significant figures.

18c1 mark

The growth of population, P, at time t years is modelled by the equation

P equals 4 straight e to the power of t


Write down the initial population.

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19a2 marks

A curve has equation

y equals a straight e to the power of b x end exponent

where and a and b are non-zero constants.

At the point open parentheses 0 comma space a close parentheses, the gradient of the curve is 12.

Find an expression for b spacein terms of a.

19b1 mark

Hence write down the equation of the curve in terms of a and x only.

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1a1 mark

The function straight g is defined by

straight g open parentheses x close parentheses equals fraction numerator 3 ln open parentheses x close parentheses minus 7 over denominator ln open parentheses x close parentheses minus 2 end fraction space space space space space space space space space space x greater than 0 space space space space space space space space space space x not equal to k

where k is a constant.

Deduce the value of k.

1b2 marks

Find the range of values of a for which

straight g left parenthesis a right parenthesis greater than 0

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2
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3 marks

Solve

2 straight e to the power of 2 x end exponent equals straight e to the power of x plus 10

giving your answer(s) to 3 significant figures.

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33 marks

Solve

2 open parentheses 2 to the power of 2 x end exponent close parentheses plus 4 equals 9 open parentheses 2 to the power of x close parentheses

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4a3 marks

Show that the equation

straight e to the power of x minus straight e to the power of negative x end exponent equals 0

has only one real solution, which you should find.

4b2 marks

Show that the equation

straight e to the power of x plus straight e to the power of negative x end exponent equals 0

has no real solutions.

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5
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3 marks

Without using a calculator, find the value of

fraction numerator 3 log subscript 6 space 216 minus ln space straight e to the power of 5 plus 4 to the power of log subscript 5 625 end exponent over denominator log space 10000 end fraction

Show the steps in your solution clearly.

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64 marks

Solve

3 to the power of 2 open parentheses x plus 1 close parentheses end exponent plus 3 equals 28 open parentheses 3 to the power of x close parentheses

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7
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3 marks

Find two values of x for which

log open parentheses x squared close parentheses equals open parentheses log space x close parentheses squared

is true.

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8a1 mark

A curve has equation

y equals 1 over a straight e to the power of negative b x end exponent

where a and b are non-zero constants.

State a condition on b to ensure the curve represents exponential decay.

8b
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2 marks

At the point open parentheses 0 comma space a close parentheses on the curve, the gradient is 10.

Use this information to find an expression for y in terms of a and x only.

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9a1 mark

A particle is travelling with velocity v ms-1 at time t seconds.

The velocity of the particle is modelled by

v equals 0.3 straight e to the power of k t end exponent

where k is a constant.

Write down the initial velocity of the particle.

9b
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2 marks

Find an expression in terms of k and t for the acceleration of the particle.

9c
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2 marks

After 12 seconds, the velocity of the particle is 0.9 ms-1.

Find the value of k, giving your answer to 3 significant figures.

9d1 mark

State a problem with the model for large values of t.

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10
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5 marks

Solve the equation

2 straight e to the power of 3 x end exponent minus 11 straight e to the power of 2 x end exponent plus 12 straight e to the power of x equals 0

giving your answer(s) to 3 significant figures.

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