When do you know to use the chain rule??(adsbygoogle = window.adsbygoogle || []).push({});

I really don't understand what this means: dr/dt = dr/ds * ds/dt

Like in one example in the book they have:

r(s) = cos2si + sin2sj + e^-3sk where s = t^4

Then they find dr/dt using the chain rule. My question is why can't you just differentiate it normally by the individual components? How would that be different?

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

Dismiss Notice

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!

# Chain Rule

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