can someone told me step by step how to simplify these two expressions?
It helps a lot to know that sin(2x)= 2 sin(x) cos(x) and that $\displaystyle cos(2x)= cos^2(x)- sin^2(x)$. You can also use $\displaystyle cos(2x)= 2cos^2(x)- 1$ and $\displaystyle cos(2x)= 1- 2sin^2(x)$.