# Math Help - Partial Derivitive Question

1. ## Partial Derivitive Question

Having trouble understanding this one:

r=sqrt(x^2 +y^2)

and

x= r cos theta

show

dr/dx * dx/dr not = 1

2. Are you asked to show

$\displaystyle \frac{dr}{dx}\cdot\frac{dx}{dr} \neq 1$

or

$\displaystyle \frac{\partial r}{\partial x}\cdot\frac{\partial x}{\partial r} \neq 1$?

3. The second one you wrote iam asked to show.

I actually thought they were both the same meaning,oops.
I worked it ou now.
Thanks for your post Prove it.