Coordinate Substitution?

[spencer]

This is technically an electromagnetics problem, but it can be solved purely mathematically.

"At what values of theta does the e-filed intensity of a z-direccted dipole have no z-component?"

This works out to be..

E = q /(4 pi eps R[sup:w40rlqrt]3[/sup:w40rlqrt]) * (r2cos(theta)+thetasin(theta))

Some sort of coordinate substitution needs to go down here, I'm just not quite sure how to go about it.
(Again, the goal is to find theta such that z is zero.)

 

[mmm4444bot]

E = q /(4 pi eps R[sup:xlkqj38q]3[/sup:xlkqj38q]) * (r2cos(theta)+thetasin(theta))

... the goal is to find theta such that z is zero ? There is no z in your equation

Also:

Is r2 a multi-character variable name?

Is eps a multi-character variable name?

 

[spencer]

Sorry i should've been more specific

E = q /(4 pi eps R3) * (r*2*cos(theta)+theta*sin(theta))

eps is epsilon (a constant)
theta is theta (a variable)
r and theta are unit vectors
E is a vector

The only variables are theta and the unit vectors r and theta.
I know z isn't in my equation - I'm having trouble with the coordinate substitution that would replace r and theta with z