$\int x\cdot\cos\left(t\right)dx$

$6\cos\left(7x\right)-3-6\cos\left(7x\right)\tan\left(x\right)+3\tan\left(x\right)=0$

$\int\sqrt{9-\left(x-3\right)^2}dx$

$-7n+5m=-13n+6n+5n$

$\int_2^5\left(\frac{3-2x^2}{\left(2x+1\right)\left(3x^2+2\right)}\right)dx$

$2xy-x-y,\:x=-2,\:y=-1$

$\arctan\left(1.7\right)$