Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

For this question, a calculator must not be used. The complex numbers $-3\sqrt{3} + i$ and $\sqrt{3} + 2i$ are called $u$ and $v$ respectively.
(i)[5]

Find the complex numbers $uv$ and $\frac{u}{v}$ in the form $x + iy$, where $x$ and $y$ are real and exact.

(ii)[3]

On a sketch of an Argand diagram with origin $O$, indicate the points $A$ and $B$ for the complex numbers $u$ and $v$ respectively. Show that angle $AOB = \frac{2}{3}\pi$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Insert $u$ and $v$ into $uv$, expand, and use $i^2=-1$

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI