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

$24x+36x^2+3-50x+25x^2+16$

$448x^2-336x+63$

$\cos\left(\theta\right)\sin\left(\theta\:\right)\left(\sec\left(\theta\:\right)+\csc\left(\theta\:\right)\right)$

$\sqrt[4]{81x^2y^{18}}$

$\left(2x+1\right)\left(2x-1\right)+\left(x+3\right)\left(x-3\right)$

$\left(\frac{1}{2}s^2-s^3\right)^2$