The question is taken from the internet site
http://farside.ph.utexas.edu/teaching/em/lectures/node33.htmlhttp://farside.ph.utexas.edu/teaching/em/lectures/node33.html
I wonder how they get the equations
I also wonder how they get this from the same site (you will get to the equation if you follow the button next and I donât believe this is related to anything in between (249) and (254))
Based on the equation





