S(e^(x(^2)+x+7)*2x+1) dx
S(x^3*lnx)dx
S(sqrt(1+ctgx))/(sin(^2)x)) dx
S((5x-2)/(1-x-6x^2))dx
S((x^5)/(x^4+3x^3-25x^2+21))dx
S((2x^2+x+3)/((x+2)*(x^2+x+1))dx