$e^{\ln\:\left(\cos\:\left(y\right)\right)}=e^{-\frac{1}{2}\ln\:\left(x^2+1\right)}$

$\int_{0}^{\frac{\pi}{4}}\frac{x}{\cos^{2}x}dx$

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

$\int x\left(3x^2+3\right)^3dx$

$-10-25+25+50$

$\int_{-2}^4\left(\frac{4}{2x-1}\right)dx$

$b+\sqrt{5b^2}$