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1. ordinary differential equations
Find the solution to

d^2y-4dy+3y=3x-1

that also satisifies, y(0)=0 and dy(0)=4

i have found the equation as it stands to be

x+1+Ae^x+Be^3x

but dont get the whole so it satisfies bit

anyone able to help?
2. Re: ordinary differential equations
you`ve got the answer, so plug in: y=0, x=0 to get one constant of integration

derive the equation, and plug in y'=0, x=4 to get the other
Last edited by Hasufel; 11-07-2012 at 10:28.
3. Re: ordinary differential equations
(Original post by Hasufel)
you`ve got the answer, so plug in: y=0, x=0 to get one constant of integration

derive the equation, and plug in y'=0, x=4 to get the other
I think that your last line is incorrect.

It should be differentiate the equation, and plug in y'=4, x =0 to get the other.
4. Re: ordinary differential equations
never mind

i won`t bother from now on
5. Re: ordinary differential equations
(Original post by Hasufel)
you`ve got the answer, so plug in: y=0, x=0 to get one constant of integration

derive the equation, and plug in y'=0, x=4 to get the other
i have no idea what you mean because all i got from doingthe first part is

0=a+b+1
6. Simultaneous equations...

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7. Re: ordinary differential equations
(Original post by burbidge)
i have no idea what you mean because all i got from doingthe first part is

0=a+b+1
Like you say:

A + B = -1

y' = Ae^x + 3Be^3x + 1, y(0) = 4, so

4 = A + 3B + 1 =>

A + 3B = 3

then solve simultaneously as div curl says to find A & B.