$\frac{dx}{dt}=4\left(1-x^2\right)$

$\lim_{x\to1}\left(\frac{x^{2}-9}{x+3}\right)$

$\frac{3x-4}{3-x}=2$

$3\:-\:\left(6\:-\:15\right)\:-\:\left(11\:-\:4\right)$

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

$\frac{1x^{10}}{1+x}$

$\frac{\cos\left(\left(\frac{\pi}{2}\right)-x\right)}{\sin\left(\:\left(\frac{\pi}{2}\right)-x\right)}=\tan\left(x\right)$