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

$5x\:-\:xy^2$

$\left(7+x\right)\frac{dy}{dx}=9y$

$15x^2y-4x^2y+6x^2y+11x^2y$

$9\cdot\left(-5-3\right)$

$\frac{dy}{dx}=\left(\frac{e^x+4x}{2y}\right)$

$3x\:-2\left(x\:-\:2\right)\:\ge\:2x$