$15\left(x^4+2x^2+15\right)$

$\int8x^{15}cos\left(x^8\right)dx$

$2\sin\left(5a\right).\sin\left(6a\right)+2\cos\left(7a\right).\cos\left(4a\right)-\cos\left(3a\right)$

$\left(e^{3x+2}\right)dx+\left(e^{x-4}\right)dy=0$

$\frac{2x+4}{x^2+4x+3}$

$\frac{\left(cos\left(x+h\right)-cos\left(x\right)\right)}{h}$

$\frac{2+2sin\left(a\right)^2}{cos\left(a\right)^2}$