Substitution to make it seperable

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SUMMARY

The discussion revolves around solving initial value problems (IVPs) involving differential equations using substitutions to make them separable. The equations presented include \(\frac{dy}{dx} + xy^{3} + \frac{y}{x} = 0\) and \(\frac{dy}{dx} + \frac{y}{x} = -xy^3\). The user initially struggled with these equations but later referenced the Bernoulli differential equation for guidance and successfully solved the problems. The substitution \(u = e^{y}\) was particularly noted as useful in transforming the equations.

PREREQUISITES
  • Understanding of differential equations, specifically Bernoulli equations.
  • Familiarity with initial value problems (IVPs).
  • Knowledge of substitution methods in solving differential equations.
  • Basic calculus concepts, including derivatives and integrals.
NEXT STEPS
  • Study the properties and applications of Bernoulli differential equations.
  • Learn about different substitution techniques for solving differential equations.
  • Explore advanced methods for solving initial value problems (IVPs).
  • Review the implications of using exponential substitutions in differential equations.
USEFUL FOR

Students preparing for midterms in calculus, mathematicians focusing on differential equations, and anyone interested in mastering initial value problems and substitution techniques.

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\acute{y}+xy^{3}+\frac{y}{x}=0
y(1)=2
using substitution u=y^{-2}

e^{y}\acute{y}=e^{-x}-e^{y}
y(0)=0
using substitution u=e^{y}

i could not make these equations seperable and solve for the IVP.
Anyone has any idea?

Edit: these problems are not homework, but for self study for preparation to the midterm.
 
Last edited:
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\frac{dy}{dx}+xy^{3}+\frac{y}{x}=0

\frac{dy}{dx}+\frac{y}{x}= -xy^3


Now read http://en.wikipedia.org/wiki/Bernoulli_differential_equation" for the rest really.
 
Last edited by a moderator:
thank you, I solved them all.
 

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