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May 5th, 2017, 06:22 PM   #1
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Solution not matching with WolfRam

I'm checking my solution with WolfRam and it's not matching. I can't see where I'm going wrong, anything obvious I'm missing?

Differential equation:
$\displaystyle 3y''+y'-2y=4+2x+e^x$

Initial conditions:
$\displaystyle y(0)=3, y'(0)=2$

My working:
working_1.jpg
working_2.jpg

Last edited by max233; May 5th, 2017 at 06:38 PM.
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May 6th, 2017, 12:39 AM   #2
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Quote:
Originally Posted by max233 View Post
I'm checking my solution with WolfRam and it's not matching.
You should check by substituting your solution into the original differential equation to see whether

$\displaystyle 3y'' + y' - 2y$
does indeed equal

$\displaystyle 4 + 2x + {e^x}$

I'm not sure it does, but it is a deal of arithmetic and I might just as easily have made a mistake there as you.

Last edited by skipjack; May 6th, 2017 at 04:56 AM.
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May 6th, 2017, 05:07 AM   #3
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Quote:
Originally Posted by max233 View Post
. . . and it's not matching.
I submitted the problem to W|A and its answer was equivalent to yours.
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