Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[5]

The complex numbers $u$ and $w$ satisfy the equations $u - w = 4i$ and $uw = 5$. Find $u$ and $w$, giving every answer in the form $x + iy$, where $x$ and $y$ are real.

(b(i))[5]

On a sketch of an Argand diagram, shade the set of points representing complex numbers $z$ that satisfy the inequalities $|z - 2 + 2i| \leq 2$, $\arg z \leq -\frac{1}{4}\pi$ and $\operatorname{Re} z \geq 1$, where $\operatorname{Re} z$ is the real part of $z$.

(b(ii))[1]

Calculate the largest possible value of $\operatorname{Re} z$ for points in the shaded region.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Remove $u$ or $w$ to produce an equation in $w$ or in $u$.

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