$\cos\:\left(x+y\right)+\cos\:\left(x-y\right)=2\cos\:\left(x\right)\cos\:\left(y\right)$

$15x^2y-30xy$

$\frac{dy}{dt}=4t+2y$

$\frac{4sin^2\left(x\right)-4sin^4\left(x\right)}{sin\left(2x\right)}=sin\left(2x\right)$

$2x+2\sqrt{2x^{3}-x-2}$

$x^2-6x+9x$

$33.701+467.6014+15$