# Integration + Trigonometry

Calculus Level 4

$\int_0^\pi \sqrt{ (\cos x + \cos 2x + \cos 3x)^2 + (\sin x + \sin2x + \sin3x)^2} \, dx$

If the value of the integral above equals $\dfrac \pi A + B\sqrt C ,$ where $$A,B$$ and $$C$$ positive integers with $$C$$ square-free, submit your answer as $$A+B+C$$.

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