Thanks for all the good input. I followed the advice to write out a few terms in the series and to note that the K terms with the indexes swapped were identical. Then I was able to see how the 1/2 went away in the equation of motion. From there I could see how to generalize the answer to more...
Here is what I had done that didn't work.
Chosing a particular point mass which I still called qa, gets rid of the summations over index a. Now I applied the Lagrangian to equation of motion formula.
d/dt(∂L/∂q^{}.a) - ∂L/∂qa = 0
The first term LHS comes out correct as...
Hello,
I need help understanding how to apply the formula for converting a Lagrangian to an equation of motion in this following specific application.
On page 4 of Zee's QTF in a Nutshell, he gives a Lagrangian (equation 1). In the following sentence he gives the corresponding equation...
Good news! I found that my error was in ignoring the derivative of the integrals appearing in Ex(z), and therefore not using the product rule when taking the first derivative with respect to z. Note that z is one of the limits of integration. The “new” terms arising from the product rule...
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I have a question regarding page 241 of “Principles of Electrodynamics” by Melvin Schwartz. He is deriving the electric field inside a conducting medium as a function of position z; by summing the incident field, contributions from slices of material to the left of z, and from slices...