# Trigo+Coordinate Geometry

Geometry Level 4

$(\cos^{2}\theta \cos^{2} \alpha +\sin^{2}\theta)(x^{2}+y^{2})=(x\cot \alpha-y\sin\theta)^{2}$ The equation above represents a pair of straight lines. If the angle between the two lines is of the form: $$m\alpha+n\theta$$, find the value of $$m+n+mn$$.

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