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How do you use the method of reduction of order to find the general solution with the given function?

xy" - 2(x+1)y' + (x+2)y = 0, Y1=e^(x)

2006-10-11 06:43:12 · 1 answers · asked by Anonymous in Science & Mathematics Mathematics

1 answers

Assume that y2(x) = v(x)y1(x) = v(x)e^x.

Then y2' = v'e^x + ve^x, and
y2'' = v''e^x + 2v'e^x + ve^x.

Plug these in to the equation:
x(v'' + 2v' + v)e^x - 2(x+1)(v'+v)e^x + (x+2)ve^x = 0,
or
xv'' + (2x - 2(x+1))v' + (x-2(x+1)+x+2)v = 0
Simplifying:
xv'' + v' = 0.
Let u=v'. Then xu' + u = 0, which can easily be solved for u. Then differentiate it and multiply it by y1(x) to get y2(x).

2006-10-11 06:54:52 · answer #1 · answered by James L 5 · 0 0

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