$tan^4t-sec^4t=-2tan^2t-1$

$\left(\:1-\cos\left(x^2\right)\right)\left(1+\cot\left(x^2\right)\right)$

$\frac{2}{5n}+6n^2-\frac{1}{10n}-20n^2$

$2x^3+28^2+98x$

$\lim_{x\to0}\left(log_{2\left(2x\right)}x^2\right)$

$\left(-32x^4+3-33x^2+10x^3+40x^5\right)\left(5x-3\right)$

$2x^2-24x+72$