Question

integral by parts:

ʃ -cosx e^9x

Answer 1

this should circle back on itself

Answer 2

?

Answer 3

ill see your ? and raise you a !!

Answer 4

sorry?

Answer 5

integrate this by parts twice and you should be able to circle back on yourself to get rid of the cycle

Answer 6

unless of course you havent even tried it yet, and thereby have no idea what the issue is

Answer 7

i got -1/9 e^9x cosx-1/9e^9x cosx

Answer 8

is that correct?

Answer 9

dunno, lets see if i can come up with something that doesnt bog down my browser to a crawl :)

Answer 10

can't be right they are both cos...

Answer 11

http://www.wolframalpha.com/input/?i=%CA%83%20-cosx%20e%5E(9x)dx&t=crmtb01

Answer 12

{S} -cosx e^9x dx =

-cos(x)
+ e^9x sin(x)
- 9 e^9x cos(x)
+ 81 e^9x ......


{S} -cosx e^9x dx = e^9x sin(x) -9 e^9x cos(x) - {S} 81 cos(x) e^9x dx

-{S} cosx e^9x dx = e^9x sin(x) -9 e^9x cos(x) - 81{S} cos(x) e^9x dx
+ 81{S} cos(x) e^9x dx + 81{S} cos(x) e^9x dx
----------------------------------------------------------------
80 {S} cosx e^9x dx = e^9x sin(x) -9 e^9x cos(x)
/80 /80
----------------------------------
{S} cosx e^9x dx = (e^9x sin(x) -9 e^9x cos(x))/80

maybe lol

Answer 13

close, real close lol

Answer 14

lol not convinced

Answer 15

i got some sign issues, but other than that :)

Answer 16

i see it, I was deriving my -cos instead of integrating it; so my signs got off lol

Answer 17

confusing :)

Answer 18

yeah, but the whole issue is in that it tends to repeat itself with integration by parts so you have to break that cycle

Answer 19

yh thanks..what grade r u in

Answer 20

ran out of grades; 35th maybe? i lost count

Answer 21

what do u mean?

Answer 22

it means that at my age, you dont have a grade to be in .....

Answer 23

oh ok u must be way past university level??

Answer 24

must be ;)

Answer 25

Dr professor?

Answer 26

usa?