Integral of exponential over polynomial

AAO
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Homework Statement


Solve the ODE: y''+x*y'-y=0

Homework Equations

The Attempt at a Solution


Since this is a variable coefficient ODE, I have used the method of reduction of order, and assumed the solution in the form: y=c1*y1+c2*y2

In this case: y1=x, and I have the reached the integral below for the second solution (y2), Can anyone tell me how to approach this integral:

v=integral[ (x^-2) * exp (-0.5*x^2) dx]
 
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AAO said:

Homework Statement


Solve the ODE: y''+x*y'-y=0

Homework Equations

The Attempt at a Solution


Since this is a variable coefficient ODE, I have used the method of reduction of order, and assumed the solution in the form: y=c1*y1+c2*y2

In this case: y1=x, and I have the reached the integral below for the second solution (y2), Can anyone tell me how to approach this integral:

v=integral[ (x^-2) * exp (-0.5*x^2) dx]
Integration by parts leaves you with an integral that is (up to some constants) the error function.
 
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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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