# Math Help - Partial derivative..

1. ## Partial derivative..

Just wondering how exactly this works...

dy/dx . (partial derivative)df/dr

=

dy/dx . x/r

I'm assuming I use the chain rule..? if so what substitution do i need to make..and how does this work..?

2. Originally Posted by dankelly07
Just wondering how exactly this works...

dy/dx . (partial derivative)df/dr

=

dy/dx . x/r

I'm assuming I use the chain rule..? if so what substitution do i need to make..and how does this work..?
Clearly there is important background information to this question that you haven't included ....