I worked a bit more on the problem but I couldn't find an equation myself nor could plot the ones you said or I found on wikipedia...
I was told that if E(r, theta) is the first equation I wrote then E(r, theta, t) would be the same thing times sin(wt) but I don't get it, How does time affect...
I was given this equation as the lines of electric fields of a dipole(two opposite charges separated by a finite distance)
e=(1/r^3)*((3cos^2(theta)-1)^2 +sin^2(2theta))^0.5
and I was asked to plot it.
I guess it must be something like this:
but when I try to plot it in wolframalpha.com in...