- #1
moooocow
- 12
- 0
Ok, In my calc book I am having problem with the first example they give in a chapter on Differentiation.
It gives the equation of [itex]V = \frac{4}{3} \pi r^3[/itex] and then it is differentiated by time = t.
[tex]\frac{dV}{dt} = \frac {dV}{dr} \frac{dr}{dt} = 4 \pi r^2 \frac {dr}{dt}[/tex]
I don't quite understand why the chain rule is being used in the first place, because [itex]4 \pi r^2[/itex] doesn't need it, and also I don't understand where [itex]\frac{dr}{dt}[/itex]comes from in the last part. I am quite confused by this basic stuff [b(] so thanks for any help.
edit : \/ Thanks for the help getting it to show up right :)
It gives the equation of [itex]V = \frac{4}{3} \pi r^3[/itex] and then it is differentiated by time = t.
[tex]\frac{dV}{dt} = \frac {dV}{dr} \frac{dr}{dt} = 4 \pi r^2 \frac {dr}{dt}[/tex]
I don't quite understand why the chain rule is being used in the first place, because [itex]4 \pi r^2[/itex] doesn't need it, and also I don't understand where [itex]\frac{dr}{dt}[/itex]comes from in the last part. I am quite confused by this basic stuff [b(] so thanks for any help.
edit : \/ Thanks for the help getting it to show up right :)
Last edited: