How Can We Solve the Differential Equation dy/dx = 35/(y^(1/8) + 25x^2)?

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Homework Help Overview

The discussion revolves around solving the differential equation dy/dx = 35/(y^(1/8) + 25x^2). The original poster attempts to find an implicit general solution of the form F(x,y) = K, indicating that the equation is separable.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the separation of variables and the integration process. There is an attempt to clarify the correct form of the equation and identify where errors may have occurred in the original poster's calculations.

Discussion Status

Some participants have provided guidance on correcting the separation of variables and have pointed out potential mistakes in the original attempt. The conversation is ongoing, with multiple interpretations being explored regarding the correct setup of the equation.

Contextual Notes

There is a focus on ensuring the equation is written correctly for integration, and participants are questioning assumptions made in the original setup. The nature of the problem as a homework assignment is acknowledged, which may impose certain constraints on the discussion.

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Homework Statement


The differential equation dy/dx= 35/(y1/8+25x2y1/8 has an implicit general solution of the form F(x,y)=K. In fact, because the differential equation is separable, we can define the solution curve implicitly by the form F(x)=G(x)+H(y)=K.
Find such solution and then give the related functions requested.


Homework Equations





The Attempt at a Solution


dy/dx=35/(y1/8(1+25x2)
1+25x2/35 dx=y1/8dy
1/35[tex]\int1+25x^2 dx[/tex]=[tex]\int y^(1/8) dy[/tex]
x+25x3/105=8/9y9/8
105(8/9y9/8)-x-253=K
so G(x)=x+25x3 and H(y)=8/9y9/8
 
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The problem is that this is incorrect and I don't know what I did wrong. Can someone see my mistake. Thank You in advance
 
dy/dx=35/(y1/8(1+25x2)
1+25x2/35 dx=y1/8dy
The bolded line is where you went wrong. Look carefully at what you did. It may be easier to see if you wrote it out "properly:"

[tex]\frac{dy}{dx} = \frac{35}{y^{1/8} + y^{1/8}25x^2}[/tex]

[tex]\frac{dy}{dx} = \frac{35}{y^{1/8}(1 + 25x^2)}[/tex]

Edit: I'm assuming the bolded line really reads ((1+25x2)/35)dx=y1/8dy
 
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So when I separate the variables it should be
y1/8dy=[tex]35/1+25x^2 dx[/tex]
 
Assuming you mean y1/8dy=(35/(1+25x2))dx, then yes, that is correct. It is more easily read as (35dx)/(1+25x2) or 35dx/(1+25x2) though, imo.
 
Okay. Thank You
 

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