Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[4]

Solve the equation $(1 + 2i)w + i w^* = 3 + 5i$. Express your answer in the form $x + iy$, with $x$ and $y$ real.

(b(i))[4]

On a sketch of an Argand diagram, shade the set of points for complex numbers $z$ that satisfy $|z - 2 - 2i| \leq 1$ and $\arg(z - 4i) \geq -\frac{1}{4}\pi$.

(b(ii))[2]

Find the least value of $\operatorname{Im} z$ for points in this region, and give the result exactly.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Substitute correctly and arrive at a valid equation in $x$ and $y$

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