- #1
Painguy
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Homework Statement
A circular ring of wire of radius r0 lies in a plane perpendicular to the x-axis and is centered at the origin. The ring has a positive electric charge spread uniformly over it. The electric field in the x-axis direction, E, at the point given by
E=kx/((x^2 +r0^2)^(3/2)) for k>0
at what point on the x-axis is greatest? least?
Homework Equations
The Attempt at a Solution
so the only thing i could really think of to do is take the derivative. the circle itself isn't changing so I assumed r0 is a constant as well as k.
[itex]E'=(k(x^2 + r0^2)^(3/2) - 3kx^2√(x^2 +r0^2))/((x^2 +r0^2)^(3/2))[/itex]after this i find the critical points
0=(k(x^2 + r0^2)^(3/2) - 3kx^2√(x^2 +r0^2))/((x^2 +r0^2)^(3/2))
0=(x^2 +r0^2)^(3/2) -3x^2√(x^2+r0^2)
im not sure what do here.
I feel like I should have solved for r0 in terms of x, but I am not sure.