What seems to be the problem? Sorry I wasn't part of the conversation so I don't know what's going on!
Also: it would be good if you could post your working out, that way we may be able to pinpoint where you're making mistakes!
Furthermore, I sometimes find it helpful that when a question is getting out of hand and messy, start it again on a new piece of paper
This is where I think we've gotten up to so far:
So you need to find
∫1314−x2−9x−2 dxYour integration is correct, we now have
∫1314−x2−9x−2 dx=[14x−31x3+9x−1]13First you substitute in the limits (3 and 1), then you subtract what you get for the lower limit from what you get with the upper limit, so you have
= [14(3)−333+39 ]−[14−31+9]Which is the area enclosed between
x=1 and
x=3 :
When
x=3 → [14x−31x3+9x−1]=36 This is correct, however:
When
x=1 → [14x−31x3+9x−1]=11As
[14+9−31]=368