Electric Potential in a region of space

1. Nov 6, 2008

quietriot1006

1. The problem statement, all variables and given/known data
The electric potential in a region of space is

, where x and y are in meters. What is the strength of the electric field at (x,y)=(2.1m,2.7m)?
The electric force is in V/m.

2. Relevant equations
E = -dV/ds

3. The attempt at a solution

I know that i have to find the partial derivatives of the x and the y but im not sure on how to get the answer from the equation given. I was thinking of making the square root into the exponential of 1/2 and then raising that to -1 to get ride of the fraction and then taking the derivatives of that but i keep getting the wrong answer. Anybody have suggestions of help they can give me please. Thanks.

2. Nov 6, 2008

tiny-tim

Welcome to PF!

Hi quietriot1006! Welcome to PF!

(btw, please use the LaTeX provided, rather than importing images of equations)

Just use the Chain Rule for differentiation …

you know how to differentiate 1/√x, don't you?

3. Nov 7, 2008

quietriot1006

Thanks for the welcome. Im still not getting the answer. Maybe im doing the chain rule incorrectly. What would i use for u or g(x) and h(x)?

4. Nov 7, 2008

(x2 + y2)

5. Nov 9, 2008

quietriot1006

I keep getting the same asnwer, -127 V/M and its not the right answer. What else can i do?

6. Nov 10, 2008

tiny-tim

Show us your calculations, and then we can see where the mistake is.