Hi, I am having difficulty picturing what to do with this double integral up to a certain point. I have scanned my work and ask that someone take a look at it and see where I got up to and tell me what I should do next. Integrate by parts? Substitution? I'm not sure. I have attached my scans to this thread. Thanks.
I sent a private message and I don't know if it was received but this is what it was:
In the question I asked, when you substitute u = r cos(theta), you get
du = - r sin(theta). When treating r as a constant, does that mean it doesn't matter if it's r^2 sin (theta) and you just integrate e^u du with respect to theta?