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

  • Thread starter Thread starter mr_coffee
  • Start date Start date
  • Tags Tags
    Confused Series
mr_coffee
Messages
1,613
Reaction score
1
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:
Physics news on Phys.org
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 \Sigma a_n (t+ 1)^n rather than \Sigma a_n t^n. 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!
 
Back
Top