Integrate sin^2x

Integrate sin^2x

To integrate sin^2x, also written as ∫sin2x dx, sin squared x, and (sin x)^2, we start by using standard trig identities to simplify the integral.

Trig Identity 1

We start by using the standard trig identity sin2x+cos2x=1 and rearrange it for sin2x. This is basic and straightforward.

Trig Identity 2

We then recall another standard trig identity for double angle where cos2x=cos2x-sin2x, and rearrange it for cos2x.

Substitute Trig Identities

We substitute the second trig identity into the first and rearrange for sin2x.

Equivalent Integration

As you can see, we now have an equivalent integral that is the same as the original, but easier to perform. Although the ½ fraction is easy to integrate, we need to focus on integrating the cos2x term, which we achieve using the u substitution method.

u Substitution Method

Using the u substitution, we integrate cos2x dx to give part of the answer.

Substitution and Final Answer

We substitute the result we gained from integrating cos2x, and then simplify to give the final answer.