# Integrating Trigonometric Functions by Double Angle Formula

## Integrating Trigonometric Functions by Double Angle Formula

Integrating Trigonometric Functions can be done by Double Angle Formula reducing the power of trigonometric functions.
\begin{aligned} \displaystyle \cos{2A} &= 2\cos^2{A} – 1 \\ &= 1 – 2\sin^2{A} \\ &= \cos^2{A} – \sin^2{A} \\ \end{aligned} \\

# Practice Questions

### Question 1

Find $\displaystyle \int{\cos^2{x}}dx$.

### Question 2

Find $\displaystyle \int{\sin^2{x}}dx$.

### Question 3

Find $\displaystyle \int{\sin^4{x}}dx$.

### Question 4

Find $\displaystyle \int{(\cos^2x – \sin^2x)}dx$.