# 2nd order differential equation

• Nov 1st 2009, 04:56 AM
nirvanakris
2nd order differential equation
solve for U(x,t), note that U=U(x,t)
Delta(Ut) + 0.1 Delta(Ux) = 0.2 Delta( Uxx)
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Answer: U(x,t) = Exp (1.17712434…x – 0.09t), Exp--> exponential
• Nov 1st 2009, 05:44 AM
HallsofIvy
Quote:

Originally Posted by nirvanakris
solve for U(x,t), note that U=U(x,t)
Delta(Ut) + 0.1 Delta(Ux) = 0.2 Delta( Uxx)

"Delta" is not standard notation. better would be just "U_t+ 0.1U_x= .2U_xx
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Quote:

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.
.
.
Answer: U(x,t) = Exp (1.17712434…x – 0.09t), Exp--> exponential
If you give no initial or boundary conditions, it is impossible to get that! Tell us what the problem really says.
• Nov 2nd 2009, 12:31 AM
nirvanakris
Quote:

Originally Posted by HallsofIvy
"Delta" is not standard notation. better would be just "U_t+ 0.1U_x= .2U_xx
.

If you give no initial or boundary conditions, it is impossible to get that! Tell us what the problem really says.

sory, ive forgot the boudaries...in fact the boudaries are given as :