$\frac{dy}{dx}\left(\cos\left(x\right)\left(y\right)=y\right)$

$-2+3\:-3.3^2\:+\:4.3^3$

$\frac{\sin\left(7x\right)+sin\left(x\right)}{sin\left(4x\right)}=1$

$\frac{2x-\:5y=\:-22}{-x+\:3y=\:13}$

$\int\left(\frac{\sqrt{81-x^2}}{9x^2}\right)dx$

$\int\:\:e^{-2y}dy$

$\int\left(2x^2-3x+1\right)e^{4x}\:dx$