$\left(x+y+x^2\right)^3$

$\lim_{x\to\frac{\pi}{2}}\left(\left(\cos\left(x\right)\right)\cos\left(\tan\left(6x\right)\right)\right)$

$\lim_{x\to6}9$

$7x^2+xy$

$\int\frac{y^3}{1-y^2}dx$

$\frac{5xy-4y-4}{7}=\frac{11xy-12y-12}{13}$

$\sin^4\left(x\right)-\cos^4\left(x\right)=2\cos\left(2x\right)$