Solving a Diff. Eq. Problem: y = (2x^-1 + Cx^4)^-1/2

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In summary, the conversation discusses a problem involving a derivative and an integrating factor. The solution involves finding v and using an integrating factor to find y. The book's solution is equivalent to the solution found in the conversation, but it is presented in a different form.
  • #1
cue928
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(x^2)y' + 2xy = 5y^3
y' + (2/x)y = 5(x^-2)(y^3) v=y^-2, y=v^(-1/2), y' = -(1/2)v^(-3/2)
-(1/2)v^(-3/2)v' + (2/x)v^(-1/2) = 5x^-2(v^-3/2)
v' - (4/x)v = -10x^-2 Integrating factor: x^-4
(skipping a few mechanical steps)
vx^-4 = 2x^-5 + C
v = 2x^-1 + Cx^4
I come up with y = (2x^-1 + Cx^4)^-1/2

Problem is the book shows y^2 = x/(2+Cx^5)? What am I missing?
 
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  • #2
y = (2x^-1 + Cx^4)^-1/2 and y^2 = x/(2+Cx^5) are equivalent. Multiply the first expression by [tex]\sqrt{x/x}[/tex].
 
  • #3
OMG, I am an idiot. I should have seen that.
 

1. What is a differential equation?

A differential equation is a mathematical equation that involves an unknown function and its derivatives. It describes the relationship between the function and its derivatives, and is used to model many real-world phenomena in physics, engineering, and other fields.

2. How do you solve a differential equation?

The process of solving a differential equation involves finding a function that satisfies the equation. This can be done through various methods such as separation of variables, integrating factors, and substitution. It may also involve finding a particular solution that satisfies given initial conditions.

3. How do you find the general solution of a differential equation?

The general solution of a differential equation is the set of all possible solutions that satisfy the equation. It typically includes a constant term, known as the arbitrary constant, which can take on any value. The general solution can be found by using integration techniques to solve the differential equation.

4. What is the role of the constant of integration in solving a differential equation?

The constant of integration, represented by "C", arises when integrating a differential equation. It accounts for all the possible solutions that differ by a constant value. In other words, it allows for the general solution of the differential equation to be represented by a family of curves instead of a single curve.

5. How do you solve a differential equation with initial conditions?

Solving a differential equation with initial conditions involves finding a particular solution that satisfies the given initial conditions. This can be done by substituting the initial values into the general solution and solving for the arbitrary constant. The resulting solution will be unique and will satisfy both the differential equation and the initial conditions.

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