Electric Potential in a region of space

AI Thread Summary
The discussion revolves around calculating the electric field strength at a specific point given the electric potential equation. The user is struggling with finding the correct partial derivatives and applying the chain rule for differentiation. Despite attempts to manipulate the equation, they consistently arrive at an incorrect answer of -127 V/M. Other participants encourage sharing calculations to identify errors and emphasize the importance of using the chain rule correctly. The conversation highlights the challenges of applying calculus concepts to physics problems.
quietriot1006
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Homework Statement


The electric potential in a region of space is
render?texml=V+%3D+%5Cfrac%7B350%7D%7B%5Csqrt+%7Bx%5E2+%2B+y%5E2+%7D%7D.gif

, 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.

Homework Equations


E = -grad(V)
E = -dV/ds

The Attempt at a Solution



I know that i have to find the partial derivatives of the x and the y but I am 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.
 
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Welcome to PF!

quietriot1006 said:
render?texml=V+%3D+%5Cfrac%7B350%7D%7B%5Csqrt+%7Bx%5E2+%2B+y%5E2+%7D%7D.gif

…I know that i have to find the partial derivatives of the x and the y but I am 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.

Hi quietriot1006! Welcome to PF! :smile:

(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? :wink:
 
Thanks for the welcome. I am still not getting the answer. Maybe I am doing the chain rule incorrectly. What would i use for u or g(x) and h(x)?
 
quietriot1006 said:
Thanks for the welcome. I am still not getting the answer. Maybe I am doing the chain rule incorrectly. What would i use for u or g(x) and h(x)?

(x2 + y2) :smile:
 
I keep getting the same asnwer, -127 V/M and its not the right answer. What else can i do?
 
quietriot1006 said:
I keep getting the same asnwer, -127 V/M and its not the right answer. What else can i do?

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