$\int e^{2x}sin\left(x\right)dx$

$\frac{2xy}{4y^2}$

$\frac{1-\text{tg}^2a}{1+\text{tg}^2a}=1-2\text{sen}^2a$

$\csc x=\frac{1+\sin x\cdot\cot^2x}{1+\sin x}$

$k^3-r^3=\left(k^2+r\right)\left(k-r^2\right)$

$\lim_{x\to\frac{\pi}{3}}\left(\cos\left(x\right)+\sin\left(x\right)\right)$

$\frac{4x^2+31x+25}{x+7}$