# Recent content by edfink1

1. ### Average Energy density and the Poynting vector of an EM wave

Hi, In Problem 9.12 of Griffiths Introduction to Electrodynamics, 4th edition (Problem 9.11 3rd edition), in the problem, he says that one can calculate the average energy density and Poynting vector as using the formula I don't really understand how to do...
2. ### Griffiths Quantum Mechanics 2nd edition Chapter 8 equation is confusing

Thank you, I get it now!
3. ### Griffiths Quantum Mechanics 2nd edition Chapter 8 equation is confusing

In Griffiths Quantum Mechanics 2nd edition, in Chapter 8 he calculates the following integral on page 323 and he gets I disagree with this result, I think the integral should be since Maybe somebody can explain why I am wrong? Also, from equation 8.24 to 8.25, he makes the assumption that...