Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[5]

With your working shown, determine the two square roots of the complex number $1 - (2\sqrt{6})i$. Write each answer in the form $x + iy$, with $x$ and $y$ exact.

(b)[5]

On a sketch of an Argand diagram, indicate the region containing the complex numbers $z$ that satisfy $|z - 3i| \leq 2$. Determine the largest possible value of $\arg z$ for points in this region.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Square $x+iy$ and match the real and imaginary parts to $1$ and $-2\sqrt6$.

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