Question

\int \:cos^2xdx

Answer 1

$\int \:cos^2xdx=\int\frac{1}{2}*(1+cos(2x))dx=\int\frac{1}{2}dx+\int\frac{1}{4}*cos(2x)d(2x)=\frac{1}{2}*x+\frac{1}{4}*sin(2x)+C$