Question 1414b

Complex Numbers

2014 Paper 2 Question 2 Variant

Question

It is given that

{w=- \sqrt{3} + \mathrm{i}.}

(a)

Without using a calculator, find an exact expression for

{w^7.}

Give your answer in the form

{r \mathrm{e}^{\mathrm{i}\theta},}

where

{r > 0}

and

{-\pi < \theta \leq \pi.}

[3]

(b)

Without using a calculator, find the three smallest positive whole number values of

{n}

for which

{w^n w^*}

is a real and positive number.

[4]