Position Varying Electric Potential

[Refrost]

http://img168.imageshack.us/img168/3786/66134795.png

Part one was simple enough, just insert the variables in the equation given

V = (5)(9²)(7) - (9)(9)(6) - (9)(7²) = 1908 V

Part two, three and four is where I am getting confused.

Usually I would use triangles to figure out components but I am unable to figure out the direction of the field just based on the information given.

I'm not sure if I am thinking about this the wrong way or if I am misunderstanding some of the information given. Any thoughts that could get me thinking in the right direction would be greatly appreciated. Thanks in advance.

 

[kuruman]

Use

$$\vec{E}=- \vec{\nabla} V$$

 

[Refrost]

Thanks for the quick response. I got it.

Just take the derivative with respect to the component you you're looking for and change the +/- sign.

Thanks!