Question

why is the integral of 1/(800-k) NEGATIVE ln, not positive ln (1/(800-k))?

Answer 1

because you have to do a u sub
set u to 800 -k
du = -1 with respect to k

Answer 2

@Austin6i6 but my teacher said we never have to use u sub in ap AB calc?

Answer 3

i am not sure of any other way to do it