ISportsFan 0 Report post Posted October 24, 2003 I may need help more often than not for this, so I will keep posting in this thread. And, I am definitely not looking for the answer to the questions, I just need some hints to help me get the answers. I have to derive Kepler's second and third laws for a math project. Of course, the first thing that popped into my head is "INTERNET! There has to be some kind of derivation for these things on there." And there is. But, I need to follow the directions in my textbook (they provide weak hints, basically), and I think it's in there so I can't look on the internet. Of course, none of you are going to believe me that I was not going to blatently copy the internet and I was only going to look at it when I needed hints (which is the truth), so I won't waste any more time talking about that. Anyway, while deriving Kepler's second law from my textbook hints, I have arrived at h = r^2(d theta/dt). The next step is to take an area, A(t), which is found with the radius vector r going along the ellipse from the time interval [t0, t]. From this, I have to prove that dA/dt = (r^2)/2 (d theta/dt). Any ideas or hints, especially from the math majors? I know this seems odd, but thanks again. Jason Share this post Link to post Share on other sites
Slayer 0 Report post Posted October 24, 2003 I just caught this now, right as I'm about to take off for the night If no one has responded with the answer by tomorrow, I'll help you again. Share this post Link to post Share on other sites
ISportsFan 0 Report post Posted October 25, 2003 I just caught this now, right as I'm about to take off for the night If no one has responded with the answer by tomorrow, I'll help you again. Thanks a lot man. I appreciate it a ton. Jason Share this post Link to post Share on other sites
Guest Olympic Slam Report post Posted October 25, 2003 If you're desperate, try looking into some Astronomy web sites. In my Astro course last semester we applied Kepler's Laws into planet's rotation around the sun. Not sure if that's of much help for what you're doing, but the whole stuff about time and elipses sharing a relationship is evident in planetary roation around the sun. Hope this helps Share this post Link to post Share on other sites
ISportsFan 0 Report post Posted October 25, 2003 Does anyone have any help for this? I assume that it involves taking the derivative of the area, which is the vector function integral from [t0-t] (r(x)) dx. But, of course, I could be wrong. And then, even after I did that, I had no idea where to go from there. Jason Share this post Link to post Share on other sites
ISportsFan 0 Report post Posted October 26, 2003 One final bump of this because my proof of his second law is due tomorrow. Jason Share this post Link to post Share on other sites
