Hey... i was hopeing somebody can help me with a homework question... its about vector calc.... taking the deriviative.(adsbygoogle = window.adsbygoogle || []).push({});

d/dx[r(t) dot r(t)] = r'(t) dot r(t) + r(t) dot r'(t) = 2r'(t) dot r(t)

I know it sounds sillly, but i was just wondering how on earth they got

2r'(t) dot r(t) ????

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

Join Physics Forums Today!

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

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

# Vector Calculus

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