# Algebra + trigo problems

Geometry Level 3

If $${ a }_{ k } > 0$$ such that $$\sum _{ 1 }^{ 2015 }{ { a }_{ k } } \quad =\quad 1$$

Let $$E = \sum _{ 1 }^{ 2015 }{ { { a }_{ k } }^{ 2 } }$$.

Let the minimum value of $$E$$ be $$x$$.

Find the value of $$\sin { (120900x) } -\cos { (60450x) } = ?$$

Note: assume that angles are in degrees.

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