$\int12y\cos\left(x\right)dy$

$\left(5+1\right)^2-\left(3\cdot2\right)^3$

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

$\lim_{x,y\to0,0}\left(\left(\frac{\left(2^x-1\right)sin\:y}{xy}\right)\right)$

$\left(8z-x\right)^2$

$3x+2x+37-7y$

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