$\lim_{x\to0}\left(4-\frac{1}{x}\right)$

$\tan^2a-\sin^2a$

$3x^2\cdot8x-7$

$4x^2y\cdot3x^5y^2$

$\lim_{x\to0}\left(\frac{5-5cos\left(x\right)}{e^x-x-1}\right)$

$\lim_{x\to\infty}\left(\left(\frac{3x+1}{3x-1}\right)^{x\cdot\left(x+1\right)}\cdot e^{-\frac{2x}{3}}\right)$

$\left(\left(x+13\right)\left(x-12\right)+\left(x+12\right)\left(x-12\right)\right)^{0,5}$