Problem 2.5: Introduction to Quantum Mechanics by David Griffiths

[@arismich9932]

Correct me if im wrong but in part d for isnt the answer (8/3)*(h bar/a)*sin(3ωt) ? also at 20:40 and 12:10 its stated that the ω=n^2*π^2*hbar^2/2ma^2 but h bar constant is h bar not h bar squared in ω equals

[@physixdaily6223]

Thank you for your feedback. You're exactly right. What I missed in the very last line was the omega factor which I forgot to add. If you add in omega in the last line, you should be able to simplify to whatever you have.

[@antoniopereirajunior865]

In the letter a of the question, you use the propriety of kronecker delta to solve those integrals, and i got that. But explain to me why, on letter c you can't use the same propriety as doing the integrals by parts. For example, can't you use x=u implies du=dx, and dv= |psi1|^2dx implies v=1? I did by this and had the expect value equal 0. I know that is wrong because it doesn't make any sense physically, but i don't got why i can't use integration by parts :( Nice video, by the way! Very very good (sorry for my poor English).

[@moazamcheema3456]

Please to solve the problems 2.11,2.12

[@physixdaily6223]

Thank you. I'll post the solutions of those then!