Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

A calculator must not be used anywhere in this question.
(a)[5]

The complex numbers $u$ and $v$ are given by the equations $u + 2v = 2i$ and $iu + v = 3$. Find $u$ and $v$, writing both results in the form $x + iy$, where $x$ and $y$ are real.

(b)[5]

On an Argand diagram, sketch the locus for complex numbers $z$ satisfying $|z + i| = 1$ and the locus for complex numbers $w$ satisfying $\arg(w - 2) = \frac{3}{4}\pi$. Determine the least value of $|z - w|$ for points on these loci.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Use a valid algebraic method to find $u$ or $v$

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