Differential equations - interval of existence

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SUMMARY

The discussion centers on the interval of existence for the initial value problem (IVP) defined by the differential equation dy/dx=(sinx)/y with the initial condition y(π/2)=1. The correct solution to this IVP is y=(1-2cosx)^(0.5). Participants debate whether the interval of existence should include the endpoints π/3 and 5π/3, ultimately concluding that it should not, as y=0 at these points, which invalidates the original equation.

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  • Understanding of differential equations and initial value problems (IVP)
  • Familiarity with trigonometric functions and their properties
  • Knowledge of continuity and existence theorems in calculus
  • Ability to analyze solutions of differential equations
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Students and professionals in mathematics, particularly those focusing on differential equations, calculus, and mathematical analysis.

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dy/dx=(sinx)/y Initial condition is y(pi/2)=1
The solution to the IVP is y=(1-2cosx)^.5
That I know is correct, but they're saying the interval of existence is when pi/3<x<5*pi/3.
Is that wrong? I think it should include the π/3 and 5π/3.
 
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No, y=0 at the endpoints. Look at what that does to your original equation.
 

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