The freemathhelp forum is not an on-line classroom. That is, we don't teach classroom material or provide lessons because many on-line sources for studying math topics already exist. The volunteers at this site don't really have time to reproduce them. Our focus is helping students who get stuck while doing exercises about which they have already learned.
Did you try googling for lessons? Try something like: how to convert from polar to rectangular
Once you've watched video lectures or studied some written lessons, going through a number of worked examples step-by-step, try your exercise again. If you're still stuck, then come back and post what you've tried. You'll then be in a position to ask specific questions about the part(s) you don't understand. Of course, if you see or hear something in a lesson or example that puzzles you, feel free to ask us about it.
Thank you. :cool: