Sum: (where Q is theta)
sin Q - 1/3sin2Q + 1/9sin3Q - 1/27sin4Q...

Okey, so using Geometric summation of an infinite series =) i get

<br />
\frac{e^(Qi)}{1 - e^(-Qi)}<br />

But when i 'realise' / rationalise it i get the numerator as e^Qi - \frac{1}{3}

And according to the answers numerator should be e^Qi...
Why is this :S?