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Edexcel A Level Further Maths

Topic questions Pure mathematics Complex arithmetic

Complex arithmetic

16 questions · 114 marks · about 2.5 hours

Complex arithmetic questions

Edexcel 9FM0 Complex arithmetic 16 questions

Paper 1: Core Pure Mathematics 1 June 2025, Question 3 5 marks

The complex number z maths symbol a maths symbol bi where a and b are real constants.

Given that fraction is purely imaginary,

(a)

show that a2 = b2

[2]
Reveal mark scheme Mark scheme for question 3(a)
(b)

Given also that zz* maths symbol 50

determine the possible complex numbers z

[3]
Reveal mark scheme Mark scheme for question 3(b)

Paper 2: Core Pure Mathematics 2 June 2025, Question 1 6 marks

In this question you must show all stages of your working. Solutions relying entirely on calculator technology are not acceptable.

Given that

Question 1, shown as an image

show that

(a)
Figure for question 1
[3]
Reveal mark scheme Mark scheme for question 1(a)
(b)

arg(zw) maths symbol arg(z) maths symbol arg(w)

[3]
Reveal mark scheme Mark scheme for question 1(b)

Paper 2: Core Pure Mathematics 2 June 2025, Question 4 10 marks

(i)

z1 maths symbol a maths symbol bi and z2 maths symbol c maths symbol di

where a, b, c and d are real constants.

Given that

Question 4, shown as an image

• z1 maths symbol z2 is real

Figure for question 4
Question 4, shown as an image

show that a maths symbol 2 and determine the value of each of b, c and d

[5]
Reveal mark scheme Mark scheme for question 4(i)
(ii)(a)

On the same Argand diagram

• sketch the locus of points z which satisfy z maths symbol 12 maths symbol 7

• sketch the locus of points w which satisfy w maths symbol 5i maths symbol 4

showing the coordinates of any points of intersection with the axes.

[2]
Reveal mark scheme Mark scheme for question 4(ii)(a)
(ii)(b)
Figure for question 4
[3]
Reveal mark scheme Mark scheme for question 4(ii)(b)

Paper 1: Core Pure Mathematics 1 June 2022, Question 1 6 marks

f(z) = z3 + az + 52 where a is a real constant

Given that 2 – 3i is a root of the equation f(z) = 0

(a)

write down the other complex root.

[1]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Hence

(b)(i)

solve completely f(z) = 0

Reveal mark scheme Mark scheme for question 1(b)(i)
(b)(ii)

determine the value of a

[4]
Reveal mark scheme Mark scheme for question 1(b)(ii)
(c)

Show all the roots of the equation f(z) = 0 on a single Argand diagram.

[1]
Reveal mark scheme Mark scheme for question 1(c)

Paper 1: Core Pure Mathematics 1 June 2022, Question 1 6 marks

f(z) = z3 + az + 52 where a is a real constant

Given that 2 – 3i is a root of the equation f(z) = 0

(a)

write down the other complex root.

[1]
Reveal mark scheme Mark scheme for question 1(a)
(b)

Hence

(b)(i)

solve completely f(z) = 0

Reveal mark scheme Mark scheme for question 1(b)(i)
(b)(ii)

determine the value of a

[4]
Reveal mark scheme Mark scheme for question 1(b)(ii)
(c)

Show all the roots of the equation f(z) = 0 on a single Argand diagram.

[1]
Reveal mark scheme Mark scheme for question 1(c)

Paper 1: Core Pure Mathematics 1 June 2022, Question 7 7 marks

Given that z = a + bi is a complex number where a and b are real constants,

(a)

show that zz* is a real number.

[2]
Reveal mark scheme Mark scheme for question 7(a)
(b)

Given that

• zz * = 18

Question 7, shown as an image
Question 7, shown as an image

determine the possible complex numbers z

[5]
Reveal mark scheme Mark scheme for question 7(b)

Paper 1: Core Pure Mathematics 1 June 2022, Question 7 7 marks

Given that z = a + bi is a complex number where a and b are real constants,

(a)

show that zz* is a real number.

[2]
Reveal mark scheme Mark scheme for question 7(a)
(b)

Given that

• zz * = 18

Question 7, shown as an image

determine the possible complex numbers z

[5]
Reveal mark scheme Mark scheme for question 7(b)

Paper 2: Core Pure Mathematics 2 June 2022, Question 1 3 marks

A student was asked to answer the following:

Question 1, shown as an image

The student’s attempt is shown below.

Figure for question 1

The student made errors in line 1 and line 3

Correct the error that the student made in

(a)(i)

line 1

Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

line 3

[2]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(b)
Question 1, shown as an image
[1]
Reveal mark scheme Mark scheme for question 1(b)

Paper 2: Core Pure Mathematics 2 November 2021, Question 1 5 marks

Given that

Question 1, shown as an image
Question 1, shown as an image
(a)

write down the exact value of

(a)(i)

|z1z2|

Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)

arg(z1z2)

[2]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(b)

Given that w = z1z2 and that arg(wn) = 0, where n maths symbolmaths symbol+

determine

(b)(i)

the smallest positive value of n

(b)(ii)

the corresponding value of |wn|

[3]
Reveal mark scheme Mark scheme for question 1(b)(ii)

Paper 2: Core Pure Mathematics 2 November 2021, Question 1 5 marks

Given that

Question 1, shown as an image
Question 1, shown as an image
(a)

write down the exact value of

(a)(i)

|z1z2|

Reveal mark scheme Mark scheme for question 1(a)(i)
(a)(ii)
Figure for question 1
[2]
Reveal mark scheme Mark scheme for question 1(a)(ii)
(b)

determine

(b)(i)

the smallest positive value of n

(b)(ii)

the corresponding value of |wn|

[3]

Paper 2: Core Pure Mathematics 2 November 2021, Question 9 8 marks

(a)

Given that |z| < 1, write down the sum of the infinite series

Question 9, shown as an image
[1]
Reveal mark scheme Mark scheme for question 9(a)
(b)

Given that z = fraction cosθ + i sinθ),

(b)(i)

use the answer to part (a), and de Moivre’s theorem or otherwise, to prove that

Question 9, shown as an image
[5]
Reveal mark scheme Mark scheme for question 9(b)(i)
(b)(ii)

show that the sum of the infinite series 1 + z + z2 + z3 + … cannot be purely imaginary, giving a reason for your answer.

[2]
Reveal mark scheme Mark scheme for question 9(b)(ii)

Paper 2: Core Pure Mathematics 2 November 2021, Question 9 8 marks

(a)

Given that |z| < 1, write down the sum of the infinite series

[1]
Reveal mark scheme Mark scheme for question 9(a)
(b)

Given that z = fraction cosθ + i sinθ),

(b)(i)

use the answer to part (a), and de Moivre’s theorem or otherwise, to prove that

Question 9, shown as an image
[5]
Reveal mark scheme Mark scheme for question 9(b)(i)
(b)(ii)

show that the sum of the infinite series 1 + z + z2 + z3 + … cannot be purely imaginary, giving a reason for your answer.

[2]
Reveal mark scheme Mark scheme for question 9(b)(ii)

Paper 1: Core Pure Mathematics 1 October 2020, Question 1 10 marks

f (z) = 3z3+pz2+ 57z+q

where p and q are real constants.

Question 1, shown as an image
(a)

show all the roots of f(z) = 0 on a single Argand diagram,

[7]
Reveal mark scheme Mark scheme for question 1(a)
(b)

find the value of p and the value of q.

[3]
Reveal mark scheme Mark scheme for question 1(b)

Paper 1: Core Pure Mathematics 1 November 2020, Question 1 10 marks

f (z) = 3z3+pz2+ 57z+q

where p and q are real constants.

Question 1, shown as an image
(a)

show all the roots of f(z) = 0 on a single Argand diagram,

[7]
Reveal mark scheme Mark scheme for question 1(a)
(b)

find the value of p and the value of q.

[3]
Reveal mark scheme Mark scheme for question 1(b)

Paper 1: Core Pure Mathematics 1 June 2019, Question 1 9 marks

Question 1, shown as an image

where a, b, c and d are real constants.

Given that í1 + 2i and 3 í i are two roots of the equation f (௘zmaths symbol

(a)

=show all the roots of f (௘z௘) = 0 on a single Argand diagram,

[4]
Reveal mark scheme Mark scheme for question 1(a)
(b)

find the values of a, b, c and d.

[5]
Reveal mark scheme Mark scheme for question 1(b)

Paper 1: Core Pure Mathematics 1 June 2019, Question 1 9 marks

where a, b, c and d are real constants.

Given that −1 + 2i and 3 − i are two roots of the equation f (z) = 0

(a)

show all the roots of f (z) = 0 on a single Argand diagram,

[4]
Reveal mark scheme Mark scheme for question 1(a)
(b)

find the values of a, b, c and d.

[5]
Reveal mark scheme Mark scheme for question 1(b)

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