×

# Problem

$\int \dfrac{\sin x + \sin^3 x}{\cos (2x) } \, dx = \,?$

Note by Brilliant Member
12 months ago

Sort by:

Hint: Start with $$y = \cos x$$, then do long division, and you get a form of $$\int \frac 1{z^2-a^2} \, dz$$. · 12 months ago

thank you very much big brother, i am able to do it now. the answer coming is " right" · 12 months ago

Pi Han Goh is correct , Let $$t=cosx \implies dx=\dfrac{dt}{-\sin{x}}$$

$$I=\displaystyle\int \dfrac{t^2-2}{2t^2-1}\cdot dt$$ · 12 months ago