Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

On an Argand diagram with origin $O$, the roots of this equation are shown by the two distinct points $A$ and $B$.
(a)[2]

Find the solutions of the equation $z^2 - 2piz - q = 0$, where $p$ and $q$ are real constants.

(b)[2]

Given that $A$ and $B$ lie on the imaginary axis, determine a relationship between $p$ and $q$.

(c)[3]

If triangle $OAB$ is equilateral instead, express $q$ in terms of $p$.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Apply the quadratic formula and $i^2=-1$

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