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## Homework Statement

The z = 0 plane is a grounded conducting surface. A point charge q is at (0,0,a), and charge 4q at (0,-2a,a).

Calculate the potential in the region z > 0.

## Homework Equations

V=∑kq/r

## The Attempt at a Solution

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Use the method of images.

V1 = kq/r+ + kq/r-

V1=kq(1/sqrt(x^2 +y^2 + (z-a)^2) - 1/sqrt(x^2 +y^2 + (z+a)^2)

V2=4kq/r+ + 4kq/r-

V2 = 4kq(1/sqrt(x^2 + (y+2a)^2 + (z-a)^2) - 1/sqrt(x^2+(y+2a)^2 + (z+a)^2))

Vtotal=ΣV=V1+V2

Vtotal=4kq(1/sqrt(x^2 + (y+2a)^2 + (z-a)^2) - 1/sqrt(x^2+(y+2a)^2 + (z+a)^2)) + kq(1/sqrt(x^2 +y^2 + (z-a)^2) - 1/sqrt(x^2 +y^2 + (z+a)^2)

**Is this the correct answer?**