One Two Three Four Five Present!

Calculus Level 4

$\large \int_{ \frac {\pi}{4} }^{ \frac { \pi }{2} } \frac {\cos 5x + \cos 4x}{1 - 2 \cos 3x} \ dx$

If the integral above equals to $$\frac1a -\frac1b$$, what is the value of $$a+b$$? Give your answer to 3 decimal places.

Details and Assumptions

• You may use the approximation $$\sqrt 2 = 1.41421$$
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