How to solve this First Order Differential Equation?

nontradstuden
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How to solve this differential equation?

dy/dx = - (3yx^(2) + y^(2)) / (2x^(3) + 3xy)


I've tried finding an integrating factor in order to make it exact, but I don't know what to do with this.


The answer is given as x^(3)y^(2) + xy^(3) = c

I'm so confused.


I separated it and found My and Nx. I've also tried finding an integrating factor, but it isn't a function of 'xy'.
 
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Presumably you have written it in the form

(3x2y+y2)dx + (2x3+3xy)dy = 0

You are correct that it is not exact. But it may have an integrating factor that is a function of x or y only which will make it exact. Look at

http://www.sosmath.com/diffeq/first/intfactor/intfactor.html

I think you will find one of those two tests works.
 
Eh, I just found out what I did wrong. Simple mistake, but took hours to find it because I kept doing it... was dividing by N instead of M...

but Thank you for your assistance!
 
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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