$f\left(x\right)=\left(senx-cosx\right)\left(senx+cosx\right)+2cos2x$

$\int x^4\left(27+x^5\right)^{\frac{1}{3}}dx$

$\left(3x-1\right)\left(2y+3\right)$

$9-\left(x-y\right)^2$

$\int\frac{2x}{x^4+2x^3+2x^2+2x+1}dx$

$\lim\:_{x\to\:0}\left(2-\frac{\sqrt{x^2+4}}{x^2}\right)$

$x2>=3$