# Can you find the relation between 1007 and 2015?

Algebra Level 4

$$\sum ^{1007} _{r=1} cos(\frac{2 \pi r}{2015})$$ can be expressed as $$(-\frac{m}{n})$$ , where $$m$$ and $$n$$ are co-prime positive integers. Calculate $$m+n$$.

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