# Why don't you simplify those fractions?

Geometry Level 2

$\displaystyle \sum_{k=1}^{145} \left [ \sin \left ( \frac {2\pi k}{8} \right ) - i \ \cos \left ( \frac {2\pi k}{14} \right ) \right ] = \frac {1}{\sqrt{a}} - i \cos \left ( \frac {\pi}{b} \right ).$ Find the sum of the positive integers $$a$$ and $$b.$$

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

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