First order differential equation

  • Thread starter mr bob
  • Start date
  • #1
38
0
Just need a hand with this one.

(dy/dx)x + 2y = x^3.ln(x)

(dy/dx) = (x^3.ln(x) - 2y)/x

Integrating factor = x^2

(dy/dx)x^2 + 2xy = (x^3.ln(x))x^2

yx^2 = INT[(x^3.ln(x))x^2]

I'm having trouble integrating the last part to complete it.

Thanks alot and in advance for any help.
 

Answers and Replies

  • #2
Tom Mattson
Staff Emeritus
Science Advisor
Gold Member
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8
mr bob said:
Integrating factor = x^2
Correct.

(dy/dx)x^2 + 2xy = (x^3.ln(x))x^2
Check this line again. You should have [itex]x^4\ln(x)[/itex] on the right side. You have an extra power of [itex]x[/itex] there.

yx^2 = INT[(x^3.ln(x))x^2]

I'm having trouble integrating the last part to complete it.
Once you clean up the right side you should integrate by parts. If you choose wisely for the parts you will only have to do it once.
 
  • #3
38
0
Thank you Tom. These differential equations can be a little tough sometimes.
 

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