$\frac{9x^2}{3x^3}$

$-x^5+16x^4-64x^3$

$\lim_{x\to0}\left(\frac{\sqrt{4+xsenx}-2}{x}\right)$

$2b+2c\cdot2c+4b$

$\int_0^{\pi}\left(1-2x\right)cos\left(wx\right)dx$

$\cot\left(-a\right)\cdot\cos\left(-a\right)+\sin\left(-a\right)=-\csc\left(a\right)$

$2x^2-\frac{1}{x}^5$