# you are correct

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Posted by T.Gracken on October 16, 2002 at 18:26:24:

In Reply to: Huh? Would you guys please look at this again... posted by Joel on October 15, 2002 at 18:29:24:

: : : The definite integral from 0 to 7 should be approx. 505.992? That's what i got but the answer key says its wrong?????????

: : if yes, then did you round/approximate prior to finishing? (as that can create significant error)

: : I calculated the definite integral (using your boundaries and result below) to 495.18

: : If that is not what the answer key has, let us know and I (or someone else will recheck the work).

: :
: : : : : Integral of [e^x sinx] =

: : : : : sin x e^x - cos x e^x - integral [ e^x sin x ]

: : : : : =[(sin x)(e^x)-(cos x)(e^x)]/2 + C

:
: I just noticed that there were more comments on this thread. I don't understand how either of you got those values. I'm getting a definite integral from 0 to 7 RADIANS as -52.64046.
: Look: e^7 is approx. 1096.6
: sin 7 is about .657
: cos 7 is about .754
: sin 0 is 0
: cos 0 is 1
: e^0 is 1
: ((.657-.754)*1096.6 - (-1))/2 = -52.68
: (Or am I messing it up someplace?)
: What DOES the answer key say?

I have no clue how I came up with the last answer I posted.

after re-evaluating the integral I came up with

-52.6404607

...sorry

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