$\int\left(x+3\right)\left(3x-1\right)^{\frac{2}{3}}dx$

$cos\left(x\right)^2=\frac{1-sin\left(x\right)^2}{cos\left(x\right)}$

$\frac{\text{sen}\alpha\cos\alpha}{\text{tg}\alpha}=1-\text{sen}^2\alpha$

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

$2.\left(2a\:+\:5\right)\:\left(2a\:-\:5\right)$

$2a+3b+3a+4b$

$18x^3-38x^2$