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

$2x-10+5x+4$

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

$\lim_{x\to0}\left(\frac{8xy\cos\left(x\right)}{x^2+y^2}\right)$

$x^2-x-2\le0$

$\int\frac{10x^2}{x^3+7}dx$

$8x+4$