[burbidge]

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?

[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

[raheem94]

(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.

[Hasufel]

never mind

i won`t bother from now on

[burbidge]

(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

[div curl F = 0]

Simultaneous equations...


This was posted from The Student Room's iPhone/iPad App

[Brit_Miller]

(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.