continous income flow, am i right?

**Question was determine the present value P of a continous income flow of c(t) dollars per year, if c(t)=30000+500t , r=7% , t=5**

note that http://s3.amazonaws.com/answer-board...4114120760.gif

can somone tell me if i did this right? this is a take home question for extra credit and i wanna make sure im right. Im a little confused because i dont know what to put as an answer. do i plug in r and t and get a numer or do i leave the equation for the answer. if i plug in r and t i get -5.451778105X10^10 which looks really wrong lol.

http://s3.amazonaws.com/answer-board...7834357504.gif.

For the first integral, let http://s3.amazonaws.com/answer-board...9281073804.gif so that http://s3.amazonaws.com/answer-board...1781071670.gif. Then

http://s3.amazonaws.com/answer-board...5531073017.gif

The second integral is integrated by parts: Let http://s3.amazonaws.com/answer-board...8656076290.gif and http://s3.amazonaws.com/answer-board...7406075411.gif. Then http://s3.amazonaws.com/answer-board...9593577636.gif, and using the above work, http://s3.amazonaws.com/answer-board...5218574643.gif. So

http://s3.amazonaws.com/answer-board...9281079700.gif. Again using the above work, this becomes

http://s3.amazonaws.com/answer-board...0843577613.gif.

Putting the above results together http://s3.amazonaws.com/answer-board...5646857857.gif