$\int\frac{x^2+9x+2}{\left(x^2+3\right)\left(x^2+5\right)}dx$

$\frac{\csc a}{\sec a}+\frac{\cos a}{\sin a}=2\cot a$

$\left(x-1\right)^2-4\left(x-1\right)-5$

$-2n+m-2m+n$

$\lim x\to inf\left(\frac{ln\left(e^{3x}+x\right)}{x^1}\right)$

$4+-1+-6$

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