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Autonomous Differential Equation

  • Thread starter n.a.s.h
  • Start date
  • #1
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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 im stuck as to what to do with the initial condition....
 

Answers and Replies

  • #2
berkeman
Mentor
57,323
7,320

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 im 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]
 
  • #3
18
0
yes i think its the general equation....
 
  • #4
Dick
Science Advisor
Homework Helper
26,258
618
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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