kill(all)$

van=facebook.com/LearningCalculus$

integrate((x^2-sin(x))/sin(x),x);

integrate((x^2*sin(x))/(sin(x)^2+cos(x)^2+2*cos(x)+1),x);

integrate((x^2*sin(x))/(sin(x)^2+cos(x)^2-2*cos(x)+1),x);

integrate((x^2-sin(x))/sin(x),x,-1,1);