$\left(13xz\right)\left(4x^2y^3z+14xy\right)$

$\int_{-1}^2\left(xy^2\right)dx$

$2sin\left(2x\right)cos\left(2x\right)=1$

$\int\frac{x-18}{\left(x+1\right)\left(x^2+1\right)}dx$

$\frac{2\sin\left(x\right)-\sin2\left(x\right)}{2\sin^2\left(x\right)}=\frac{\sin\left(x\right)}{1+\cos\left(x\right)}$

$\left(a-b^2\right)\left(a+b\right)$

$\sin^2\alpha-\cos^2\alpha=\cos2\alpha$