I have been reading W.M. Smart's "Textbook on Spherical Astronomy," and have a question about how to solve exercise 8, p. 24. [ http://tinyurl.com/chbbjc ].
If anyone can help me on this, I would be grateful. I've solved all the previous exercises, so I'm confident that I understand the material, but the only things I can think of to solve this involve horrendously long substitutions which I'm not able to simplify. If this is in fact the only way to the answer, I'd prefer to know in advance that I'm on the right track.