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Complex numbers 2 — Question 6

QCAA 2020, Paper 1 · 1 mark

Q6 · 2020 · Technology-freeSimple familiar1 mark

QUESTION 6

Given

z=2-2i

and

w=-3+i

, calculate

z^2-\overline{w}

.

(A)

3-9i

(B)

3-7i

(C)

11-9i

(D)

11-7i

ABCD

Question linkOriginal paper

WORKED SOLUTION

Answer B

1 mark

ANSWER

B

Worked solution

z^2=(2-2i)^2=-8i

and

\overline{w}=-3-i

. Therefore

z^2-\overline{w}=-8i-(-3-i)=3-7i

.

Selects option B.

[1 mark]

Worked explanation by QCE Vault; correct option verified against the QCAA answer key.

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