If I=int(e^x)/(e^(4x)+e^(2x)+1) dx. J=int(e^(-x))/(e^(-4x)+e^(-2x)+1) dx. Then for an arbitrary constant c, the value of J-I equal to
int x^2 e^(3x) dx=............ A) (1/3) x^2 e^(3x) - (2/9) x e^(3x) + (2/27) e^(3x) + c B) -(1/3) x^2 e^(3x) - (2/9) x e^(3x) + (2/27) e^(3x) + c C) (1/3) x^2 e^(3x) + (2/9) x e^(3x) - (2/27) e^(3x) + c D) (1/3) x^2 e^(3x) - (2/9) x e^(3x) - (2/27) e^(3x) + c