My Math Forum Solution not matching with WolfRam

 Differential Equations Ordinary and Partial Differential Equations Math Forum

 May 5th, 2017, 06:22 PM #1 Newbie   Joined: Mar 2016 From: Australia Posts: 20 Thanks: 1 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.
May 6th, 2017, 12:39 AM   #2
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Joined: Jun 2015
From: England

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Quote:
 Originally Posted by max233 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.

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

 Tags matching, solution, wolfram

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