$$3^1\cdot\sqrt{841}+\left(-7\right)^2+\left(-5\right)^3$$

$$4\cos^2x-4\sin^2x=1$$

$$\left(10m^4-\:5\right)\left(10m^4+\:5\right)$$

$$5x\:-\:6\:=\:-11$$

$$\csc\left(22.5\right)$$

$$\lim_{x\to\infty}\left(\frac{\sqrt{x^2+1}}{\sqrt[3]{x^3-1}}\right)$$

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