I've been thinking about this problem for HOURS, even days. Its not at all like I'm trying to avoid that. This material is simply not familiar to me. You clearly have both experience and expertise. Maybe you can't recall a time when you didn't know this, and it now seems simple. But from my perspective, its very difficult, very frustrating.
I'm an experienced woodworker. I would never imagine that you could enter my shop and produce anything by asking you to think about it. I'd show you what you didn't know, even simply addition of fractions and how to use tools, read drawings, design, select materials, etc, in order to build your skills. I'd watch to see what you DID know, and build on that. The process would be rewarding to both of us.
I really appreciate your help, and I realize you are volunteering here. This is NOT material or technique that was covered in my class. My job, apparently, is to teach myself this part of trig.
Thanks for your help. I'll think some more, and maybe I'll get it.