Confused on the directions Airy's equation, series solutions weee

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Homework Help Overview

The discussion revolves around finding a series solution for Airy's equation, specifically about the point x = -1. Participants are trying to clarify the meaning of this point in the context of the equation and the requirements set by the professor.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the form of Airy's equation and whether the original poster can use a specific equation for their series solution. There are questions about the variable with respect to which the differentiation is performed and the implications of the series solution about x = -1.

Discussion Status

Some participants have offered guidance on how to approach the series solution, suggesting the use of a different variable form. Others are reflecting on their own attempts and checking for correctness in their work, indicating an ongoing exploration of the problem.

Contextual Notes

There is confusion regarding the notation and the specific variable used in the equation, as well as the initial conditions that may apply to the series solution. Participants are also addressing potential errors in their calculations and interpretations.

mr_coffee
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Find a series solution for Airy's equation about x=-1, what does this about x=-1 mean?

Here is Airy's equation:
y''+p(t) y'+q(t) y=0.

THe professor doesn't give any 2nd order Differential equation, just the directions of:
Fridays Homework problem

Is to find a series solution for Airy's equation about x=-1

Can i use this as my equation?
y''-t y=0
and then:

img1.gif


img2.gif


img3.gif


img4.gif


img6.gif


img7.gif


img8.gif


img9.gif


img10.gif


These equations are known as the "recurrence relations" of the differential equations. The recurrence relations permit us to compute all coefficients in terms of a0 and a1.

We already know from the 0th recurrence relation that a2=0. Let's compute a3 by reading off the recurrence relation for n=1:

img12.gif


img13.gif

But what is this thing all about x=-1?

Thanks!
 
Last edited:
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Either you or your teacher is really confused!

First of all, y"+ p(t)y'+ q(t)y= 0 is NOT "Airy's equation". That is the general form of a linear homogeneous equation with variable coefficients.
Airy's equation, specifically y"- ty= 0, is a special case of that.

Second "solve y"- ty= 0 with a series solution about x= -1" makes no sense because there is no "x" in the equation! You must have either
"Solve y"- ty= 0 with a series solution about t= -1" (y" is understood to be differentiation with respect to t) or "Solve y"- xy= 0 with a series solution about x=-1" (y" is understood to be differentiation with respect to x).

Use [itex]\Sigma a_n (t+ 1)^n[/itex] rather than [itex]\Sigma a_n t^n[/itex]. If, for example, you were given initial conditions at t= -1 rather than t= 0, that form would make it easier to apply them.
 
Ivey if i already have the general solution to aries equation, can i just make alitle modifcation to it for x= -1?
http://www.soton.ac.uk/~jhr/MA273/img305.png

http://www.soton.ac.uk/~jhr/MA273/img319.png
 
Last edited by a moderator:
Ahhh n/m, i c i can't just do that, i will try it with (t+1) like u said! thanks
 
Did i do this right?>

Ivey and everyone, i think i did this right, its a long problem, but I wrote what i was going to do next so I think its easy to follow, did I do this correctly? This is the first type of problem I did like this so I'm making sure i didn't leave out somthing!

http://suprfile.com/src/1/2ur1zj/lastscan1.jpg
http://suprfile.com/src/1/2us9rp/lastscan2.jpg

Thanks!
 
Last edited by a moderator:
I went over it again and i caught a small error i think:
i had
a2 + ao + ...
should have been:
2a2 + ao
wewt.
 
I presented it today and it was correct! weee!
 

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