Question

when finding the area between 2 curves, why is this step "necessary"?

Answer 1

"Now (1) and (2) are perfectly serviceable formulas, however, it is sometimes easy to forget that these always require the first function to be the larger of the two functions. So, instead of these formulas we will instead use the following “word” formulas to make sure that we remember that the formulas area always the “larger” function minus the “smaller” function." - Pauls Calculus Notes. And other texts as well