$$\left(1+tan^2x\right)cos\left(2x\right)=\:1-tan^2x$$

$$\int tan^{-1}y+cos\left(x+2y\right)dx$$

$$a+3^4$$

$$24-672:\left(-36-5.12\right)-15$$

$$\int x\:5^{x^2+2}dx$$

$$\lim_{x\to0}\left(\ln\left(x\cdot2\right)\right)$$