Quantum Chemistry Levine 7th Edition: Chapter 3 - Exercise, Pg. 36

As an undergrad, I was studying quantum chemistry and trying to solve problems from Quantum Chemistry by Ira N. Levine. There were times where I frantically looked for solutions online and ended up finding a one word answer or a numerical answer without any explanation whatsoever. That of course motivated me to work by myself, and I spent hours solving those problems. I always felt that it would be super helpful if there was a solution manual or a video that explained the solution step-by-step. This series of videos is an attempt at helping students understand quantum chemistry problems while explaining the key concepts. In a series of videos, I will be solving the questions of exercise problems in Quantum Chemistry, 7th edition, by Ira N. Levine. This is a video of me solving exercise problem on Pg 36 of Chapter 3, Operators. I tried my best to present a detailed solution to the problem. Please feel free to ask any doubts or clarifications regarding this problem in the comments. I will make sure to address all of your questions over the comments! I will be happy to make another teaching video clarifying your doubts. Hope you find this helpful! :)