Mathematics 9709 · AS & A Level · Complex numbers

Complex numbers — practice question

(a)[5]

Without a calculator, use the quadratic formula to solve $(2 - i)z^2 + 2z + 2 + i = 0$. Write the solutions in the form $a + bi$.

(b)[5]

The complex number $w$ is given by $w = 2e^{\frac{1}{4}\pi i}$. On an Argand diagram, points $A$, $B$ and $C$ correspond to $w$, $w^3$ and $w^*$ respectively (where $w^*$ denotes the complex conjugate of $w$). Draw the Argand diagram showing points $A$, $B$ and $C$, and calculate the area of triangle ABC.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Solve by using the quadratic formula and simplifying the expression

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