$\lim_{x\to\frac{\pi}{2}}\left(\frac{tan\left(26x\right)}{tan\left(21x\right)}\right)$

$\int x^9e^{8x}dx$

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

$2x^2-6x-20\ge0$

$\frac{d}{dx}3x^4=4x^{2\:}-1.5x^{-4}$

$\frac{dy}{dx}=\sqrt{3x-2}y\left(1\right)=5$

$22ab+\left(a+b\right)=93$