$\lim_{x\to0}\left(\frac{3x^2}{\tan x^2}\right)$

$\left(39-2x\right)^2$

$\frac{dy}{dx}=\frac{2x^2-1}{y}$

$\int\frac{1}{2}\left(5x-3\right)^6dx$

$\frac{x^{3}+3x^{2}-7x+5}{6x-3}$

$8\cdot m\left(5\cdot t-6\right)+\left(5\cdot t-6\right)$

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