Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[4]

Without a calculator, solve $3w + 2i w^* = 17 + 8i$, where $w^*$ is the complex conjugate of $w$. Give your answer in the form $a + bi$.

(b)[5]

On an Argand diagram, the loci $\arg(z - 2i) = \frac{1}{6}\pi$ and $|z - 3| = |z - 3i|$ meet at the point $P$. Write the complex number for $P$ in the form $re^{i\theta}$, giving the exact value of $\theta$ and $r$ correct to 3 significant figures.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Write down or infer $3a+3bi+2i(a-bi)=17+8i$

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