What kind of problem is this. (Seperable or Bernoullis) / Diff EQ

Squizzel
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Homework Statement



xy^2 dy/dx = y^3 - x^3 , y(1) = 2

Homework Equations


The Attempt at a Solution



It says to solve the initial value problem. I am assuming it is not a Bernoulli, but I can't seem to separate it. What should I do?Thanks

This is what I get when I separate it, is this right?y^2-y^3 dy = -x^2 dx
 
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Squizzel said:

Homework Statement



xy^2 dy/dx = y^3 - x^3 , y(1) = 2


Homework Equations





The Attempt at a Solution



It says to solve the initial value problem. I am assuming it is not a Bernoulli, but I can't seem to separate it. What should I do?


Thanks

This is what I get when I separate it, is this right?


y^2-y^3 dy = -x^2 dx

xy^2 dy/dx = y^3 - x^3
dy/dx = y/x - x^2/y^2
 
Squizzel said:

Homework Statement



xy^2 dy/dx = y^3 - x^3 , y(1) = 2

Homework Equations



The Attempt at a Solution



It says to solve the initial value problem. I am assuming it is not a Bernoulli, but I can't seem to separate it. What should I do?

Thanks

This is what I get when I separate it, is this right?

y^2-y^3 dy = -x^2 dx
How do you get that last line?

It should be y2 dx - y3 dy = -x2 dx, which is not separated.

Try the substitution, y = xv .
 
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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