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

$\int_{\frac{\pi}{6}}^{\frac{\pi}{2}}\left(\frac{\cos\left(x\right)}{\sin^7\left(w\right)}\right)dx$

$\int\left(x^3\sqrt{\left(12+x^4\right)}\right)dx$

$12-c=8$

$3\sqrt{81}x^3y^4$

$\int\:\frac{\left(sen^2x\left(cot^2x+1\right)\right)}{cosx+senx}\:dx$

$8x-7=9$