This is regarding problem 1.11 step 3 and 4 in the molecular quantum mechanics book.
in step 3, how come the [v(x),x] part goes to 0? because they communte? how do we know this? in step 4, how do we get from the first line to the second?

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

Noel is hoping to make a profit (in $) on the school play and has determined the function describing the profit to be f(t) = 8t – 2654, where t is the number of tickets sold. what does the number 8 tell you?

In a survey of 1015 adults, a polling agency asked, "when you retire, do you think you will have enough money to live comfortably or not. of the 1015 surveyed, 534 stated that they were worried about having enough money to live comfortably in retirement. construct a 90% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement.