I was reading on planetary motion and have gotten hung up on a "rearrangement of terms" that the author skimmed over. It reads that:(adsbygoogle = window.adsbygoogle || []).push({});

r=e(k+rcos(θ))=(ek)/(1-ecos(θ))

It's been a while since I've been in a math class: I just can't follow how to get from a to b. Is there anyone who can walk me through this like I'm twelve?

Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Rearranging terms in Trig equation

**Physics Forums | Science Articles, Homework Help, Discussion**