Autonomous Differential Equation

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Homework Help Overview

The discussion revolves around solving an autonomous differential equation of the form dy/dt = 0.5(100 - y) with the initial condition y(0) = 20. Participants are exploring the implications of the equation and the initial condition.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the general solution found, which involves a logarithmic expression. There are questions regarding the meaning of the variable "I" and its relation to the solution. Some participants express uncertainty about how to incorporate the initial condition into the solution.

Discussion Status

The discussion is ongoing, with participants questioning the steps taken to arrive at the general solution and expressing confusion about the absence of the variable t in the context of applying the initial condition. There is a recognition of potential errors in the reasoning process.

Contextual Notes

Participants note the challenge of applying the initial condition due to the lack of a time variable in the derived expression, which raises questions about the correctness of the solution approach.

n.a.s.h
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Homework Statement


solve the following...


dy/dt= 0.5(100-y) with initial condition:y(0)=20

Homework Equations





The Attempt at a Solution



i found the general equation to be I=0.5Ln |100-y|+c
but I am stuck as to what to do with the initial condition...
 
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n.a.s.h said:

Homework Statement


solve the following...


dy/dt= 0.5(100-y) with initial condition:y(0)=20

Homework Equations





The Attempt at a Solution



i found the general equation to be I=0.5Ln |100-y|+c
but I am stuck as to what to do with the initial condition...

What's "I"?

And you are saying that 0.5 * ln |100-y| + c is some kind of a solution to this DE?

[tex]\frac{dy}{dt} = \frac{100-y}{2}[/tex]
 
yes i think its the general equation...
 
n.a.s.h said:
yes i think its the general equation...

I would say put t=0 and y=20 into that solution and then solve for the constant c, but I can't. Because there is no t. That's a problem. Can you show us how you got it? I think there's some other errors on the way.
 

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