Sarahisme Posted May 24, 2006 Posted May 24, 2006 Hi guys, i was hopeing someone would be able to guide me through this problem. for part (a) i get the transformed equation to be [math] \frac{d^2y}{ds^2}+\frac{4}{s}\frac{dy}{ds} = -\lambda y [/math] i am not 100% sure this is correct, although i have been through the working about 5 times now as for the rest of the question, well, i guess i really need to get part (a) before i can attempt the rest hey? and i don't really get this eigenvalue/vector stuff for functions :S i suppose (a) isnt really my problem, its the rest of the question that is really giving me a hard time! Thanks -Sarah
Sarahisme Posted May 24, 2006 Author Posted May 24, 2006 to be specific, its parts © & (d) that i don't know how to do, just can't quite figure out anything reasonable, other than a trivial solution! :S
Sarahisme Posted May 24, 2006 Author Posted May 24, 2006 let me see, well i've work out that the general solution is y(x) = Asin(((lambda)^0.5)/x)) + Bcos((((lambda)^0.5)/x)) but i don't see how to use y(1) = 0 and y(2) = 0 because neither cancels either term.... :S
Yggdrasil Posted May 24, 2006 Posted May 24, 2006 for © you shoud find that the p(x) obtained in (b) is zero at the boundaries (x=a and x=b). Therefore, at the boundaries: q(a)y = (lambda)r(a)y q(b)y = (lambda)r(b)y which has solutions only for certain values of lambda. These lambda are your eigenvalues. Also, if you want to look up more resources on this topic a Strum Liouville system is another name for the self-adjoint form of a differential equation.
Sarahisme Posted May 25, 2006 Author Posted May 25, 2006 for © you shoud find that the p(x) obtained in (b) is zero at the boundaries (x=a and x=b). Therefore' date=' at the boundaries: q(a)y = (lambda)r(a)y q(b)y = (lambda)r(b)y which has solutions only for certain values of lambda. These lambda are your eigenvalues. Also, if you want to look up more resources on this topic a Strum Liouville system is another name for the self-adjoint form of a differential equation.[/quote'] i am little confused. i get for part (b) that p(x) = x^2 q(x) = 0 r(x) = 1/x but p(x) isnt 0 at x=1 or x=2 and q(a)y = (lambda)r(a)y q(b)y = (lambda)r(b)y can't be done because q(x) = 0. also the question asks to find the evals etc. from part (a). i think i'm a bit lost i am guessing all that i have just said is wrong, so please please correct me! -Sarah
Sarahisme Posted May 25, 2006 Author Posted May 25, 2006 i think i need to solve : [math] Asin(\sqrt(\lambda)) + Bcos(\sqrt(\lambda)) =0 [/math] [math] Asin(\frac{\sqrt(\lambda)}{2}) + Bcos(\frac{\sqrt(\lambda)}{2}) = 0[/math] but i just can't figure out how!
Sarahisme Posted May 25, 2006 Author Posted May 25, 2006 don't worry i've figured it out! thanks for the assistance Yggdrasil
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