Derive equations for Electric Field/Electric Potential

[Renaldo]

Homework Statement

(a)
A ring with charge Q and radius R is in the yz-plane and centered on the origin. What is the electric potential a distance x above the center of the ring? (Use any variable or symbol stated above along with the following as necessary: k.)

(b)
Derive the electric field from this relationship. (Use any variable or symbol stated above along with the following as necessary: k.)

Homework Equations

V = U/q
U = -qEr
E = kQ/r²

r = (x²+R²)^0.5

The Attempt at a Solution

I got problem (a) correct. I combined the above equations which resulted in

kQ/r

kQ/(x²+R²)^0.5

For (b), it wants the answer in i + j + k.

j and k are 0.

V = qEr/q
V = Er
E = V/r

E = kQ/r²

E = kQ/(x²+R²)

This is not the correct answer for i. The problem is due in 1 hour, 30 minutes.

 

[Renaldo]

Well, it turns out that I was able to figure this one out just in time.