$\lim_{x\to\infty}\left(\frac{2x^2+1}{6+x-x^2}\right)$

$-\frac{4}{5}+\cos^2\left(x\right)=1$

$\lim_{x\to\frac{\pi}{2}}\left(cos\left(x\right)sec\left(5x\right)\right)$

$3xy^2-3xy^2z-2xyz^2+xyz^2$

$5+x<-1$

$\frac{\sin^2\left(x\right)}{\sec\left(y\right)-1}$

$\int_t^{\infty}\frac{1}{22}\left(e^{-\frac{z}{22}}\right)dz$