What is intsin^2(x) dx?

1 Answer
Dec 15, 2014

We can solve this by expressing *sin ^2 (x) in terms of a function in the first power.

From the equation:

cos 2x = cos ^ 2 (x) - sin^2 (x)

and the equation

sin^2 (x) + cos^2 (x) = 1

cos ^2 (x) = 1 - sin^2 (x)

then. we substitute to the first equation

cos 2x = 1 - sin^2 (x) - sin ^2(x)

simplifying,

sin ^2 (x) = (1 - cos 2x)/ 2

substitute to the original problem

int [(1-cos 2x)/2]dx

(1/2)int(1 - cos 2x)dx

(1/2)[ intdx - intcos 2xdx

(1/2)[x - sin 2x*intd(2x)]

(1/2)[x - (sin 2x) * 2*1]

x/2 - sin 2x + c