Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

The complex number $2 + 2i$ is represented by $u$.
(i)[2]

Find the modulus and the argument of $u$.

(ii)[4]

Sketch an Argand diagram that displays the points for the complex numbers $1$, $i$ and $u$. Shade the set of points for the complex numbers $z$ that satisfy both inequalities $|z - 1| \leq |z - i|$ and $|z - u| \leq 1$.

(iii)[3]

Using your diagram, determine the value of $|z|$ for the point in this region whose $\arg z$ is least.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Obtain the modulus $\sqrt8$.

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