Math Problem Statement

the DE y'-(1/x)y=(-2/x^2) *y^(-5/3)

Solution

The differential equation given is:

y1xy=2x2y53y' - \frac{1}{x}y = -\frac{2}{x^2} y^{-\frac{5}{3}}

This is a nonlinear first-order differential equation. To solve this, we could attempt a substitution or a transformation that simplifies the nonlinear terms.

Step-by-step process:

  1. Rewrite the equation:

    y=1xy2x2y53y' = \frac{1}{x}y - \frac{2}{x^2} y^{-\frac{5}{3}}

  2. Look for a substitution:

    A good approach is to try a substitution of the form z=y1/3z = y^{1/3}, which might simplify the powers of yy. Since y=z3y = z^3, we have:

    y=3z2dzdxy' = 3z^2 \frac{dz}{dx}

    Substituting y=z3y = z^3 and y=3z2dzdxy' = 3z^2 \frac{dz}{dx} into the original equation, we get:

    3z2dzdx=1xz32x2z5333z^2 \frac{dz}{dx} = \frac{1}{x} z^3 - \frac{2}{x^2} z^{-\frac{5}{3} \cdot 3}

    Simplify the powers of zz:

    3z2dzdx=1xz32x2z53z^2 \frac{dz}{dx} = \frac{1}{x} z^3 - \frac{2}{x^2} z^{-5}

  3. Divide through by z2z^2:

    3dzdx=zx2x2z73 \frac{dz}{dx} = \frac{z}{x} - \frac{2}{x^2 z^7}

  4. Simplify further:

    dzdx=z3x23x2z7\frac{dz}{dx} = \frac{z}{3x} - \frac{2}{3x^2 z^7}

Now, this is still a first-order differential equation in zz. We could attempt further analysis or an integrating factor, but this substitution has simplified the powers of yy.

Would you like to continue solving this transformed equation or try a different method?

Related Questions:

  1. How do you recognize suitable substitutions for nonlinear differential equations?
  2. What are the methods for solving first-order nonlinear differential equations?
  3. How does substitution simplify solving complex DEs?
  4. What is an integrating factor, and when do you use it?
  5. How do you solve first-order separable differential equations?

Tip: Substitution techniques are often key when dealing with nonlinear DEs, transforming them into more familiar forms.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Differential Equations
Substitution Method
Nonlinear First-order Differential Equations

Formulas

y' - \frac{1}{x}y = -\frac{2}{x^2} y^{-\frac{5}{3}}
y = z^3
y' = 3z^2 \frac{dz}{dx}
Substituted equation: 3z^2 \frac{dz}{dx} = \frac{1}{x} z^3 - \frac{2}{x^2} z^{-5}

Theorems

Substitution for nonlinear differential equations
Methods for solving first-order DEs

Suitable Grade Level

University-level mathematics or advanced high school calculus