$\left(\frac{\cos\left(b\right)\sec\left(b\right)}{\cot\left(b\right)}\right)\left(1-\sin^2\left(b\right)\right)$

$x^2y-2y=0$

$6x^3+13x^2-13x-20$

$\lim_{x\to-\pi}\:\frac{10cosx+10}{\left(x+\pi\right)^2}$

$\left(2x-4\right)\left(x+4\right)$

$-9x+4=-3x+28$

$y=e^{\ln\left(e\right)^{\sin\left(x^2\right)^2}}$