$\int sen\frac{x}{4}\cdot\cos\left(4x\right)dx$

$\lim_{x\to2.9}\left(\frac{x^2-9}{x-3}\right)$

$-9+10\left(1-3y\right)$

$10\frac{d}{dx}-600=-y$

$e=\text{sen}\theta.\cos\theta.\text{csc}\theta$

$\int\left(x^2-1\right)\sqrt{2x+1}dx$

$\left(2x+1\right)\frac{dy}{dx}+y^2=0$