I'm fairly sure I discovered a bug with the Maple 17 Calculus Integration tutor.

I was working on int((x^2+2*x)*cos(x), x);.

The first step that the tutor wants you to do is to rewrite the integral by factoring out an x from the first term, and changing cos(x) to -sin(x).

The next step is to rewrite it again, this time changing sin to cos, making the intergal  -x(x+2)cos(x)

Next, the tutor distributes the X again, making the integral -(x^2+2*x)*cos(x). Essentially it changed the integral from positive, to negative. It also distributes to cos in the same step, but that's irrelevant.

Maple itself gets the answer that agrees with the textbook solution, and the tutor agrees as well if you fix the change of sign problem.

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