$\left(-\:3.756\right)\cdot9$

$\int_3^{+\infty}\frac{\left(arctanx\right)^4}{1+x^2}dx$

$x^4-2x^3+4x^2$

$\int_1^{\infty}\frac{\left(x^2+5x\right)}{\left(x^2+1\right)^{\left(\frac{3}{2}\right)}}dx$

$6\left(\left(4x-1\right)\right)$

$f\left(x\right)=\frac{\left(x^6\tan\left(x\right)\right)}{\left(e^x\sin\left(x\right)\right)}$

$\frac{cos2\left(x\right)}{1-\sin\left(x\right)}=1\:+\:sin\left(x\right)$