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RadiationX
Jun15-05, 11:20 AM
I need to solve this D.E.

x^2y''-xy' + y = x^3

i'm supposed to use the variation of parameters technique.

in that technique i need to get a coeffecient of 1 in the first postion of y'' and then sove the homogenous D.E.

y''-\frac{y'}{x} +\frac{y}{x^2}=0

the above leads to

m^2-2m +1=0

now solving this i get

C_1x +C_2tx

my problem is that i don't know how to move forward with
C_2tx

how do i proceed

dextercioby
Jun15-05, 11:34 AM
It's an Euler equation.You need to transform it into a linear equation with constant coeffs.Read the theory again and identify the substitution you need.

Daniel.

RadiationX
Jun15-05, 11:39 AM
do you mean that this is a Bernoulli equation?

dextercioby
Jun15-05, 12:09 PM
I told u it was/is an Euler eqn.

Make the sub

x=e^{t}

y(x)\longrightarrow \bar{y}(t)

Daniel.

RadiationX
Jun15-05, 12:11 PM
ok. i'll figure it out