Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[6]

Show every step and, without a calculator, solve the equation $(1 + i)z^2 - (4 + 3i)z + 5 + i = 0$. Present your solutions in the form $x + iy$, where $x$ and $y$ are real.

(b)[4]

The complex number $u$ is $u = -1 - i$. On a sketch of an Argand diagram, mark the point for $u$. Shade the region whose points represent complex numbers satisfying the inequalities $|z| < |z - 2i|$ and $\frac{1}{4}\pi < \arg(z - u) < \frac{1}{2}\pi$.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Find $z$ by using the quadratic formula

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