# Easier than it looks

Algebra Level pending

If $$z + \dfrac1z = 2\cos \theta$$, and $$z$$ is a complex number, $$n$$ is a variable, what is the value of $$z^n + \dfrac1{z^n}$$?

A) $$2ni \sin(n\theta )$$.
B) $$2i \sin(n\theta )$$.
C) $$2i$$.
D) $$2 \sin(n\theta )$$.

Clarification: $$i=\sqrt{-1}$$.

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