Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[5]

Determine the complex number $z$ that satisfies the equation $z^* + 1 = 2iz$, where $z^*$ represents the complex conjugate of $z$. Write your answer in the form $x + iy$, where $x$ and $y$ are real.

(b(i))[4]

On an Argand sketch, shade the set of points representing complex numbers that satisfy the inequalities $|z + 1 - 3i| \leq 1$ and $\operatorname{Im} z \geq 3$, where $\operatorname{Im} z$ is the imaginary part of $z$.

(b(ii))[2]

Find the difference between the largest and smallest values of $\arg z$ for points in this region.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: After substitution, produce a valid equation in $x$ and $y$

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