You are correct. It is Dr BRAD Osgood. The good Dr's material (but not, unfortunately, his attempts at humor) is excellent, but the recording quality leaves much to be desired. Along about the fourth or fifth lecture, the cameraman goes to sleep and an entire board of equations goes permanently missing. He is also a bit late panning to the current board in some of the other lectures and several lectures have such problems with lighting that only the chalked material is-- barely--visible. But you can follow it quite well just from the audio and the notes.
I don't think the problem is just that that the subject line has been changed; rather it's a whole new post. The OP seems to have started two new threads, both of which should be branches of your "Integrating exp(-x^2)" question. [I know your original question has been answered, but the way we did it was to note that int exp(-x^2) dx * int exp(-y^2) dy = int exp(-x^2)exp(-y^2) dx dy = int exp(-(x^2 + y^2)) dx dy and then change to polar co-ordinates. I think it was done in first year probability and statistics; but Jacobians and general transformations of integrals 'twixt different co-ordinate systems would have come in the second year, so I fancy that 2D Cartesian to polar was done as a special case just to do that integral (or a close relative) in connection with the normal distribution.]
