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?????????
: : is your calculator in the correct mode (radian measure)?
: : 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
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