推 wil0829ly:感謝i大 我研究一下@@ 05/07 16:52
推 ntust661:bessel 耶 05/08 18:10
推 ytyty:看到bessel 先拜再說m(_ _)m 05/08 22:05
※ 引述《wil0829ly (汪汪)》之銘言：
: http://www.lib.nsysu.edu.tw/exam/master/eng/mech/mech_92.pdf
: 請問第五題要怎麼做
: 答案是B
: 有請高手幫忙
: 謝謝!!
let y=zx^-(1/2)
y'=λx^-(1/2)z'-(1/2)x^-(3/2)z
y''=λ^2x^-(1/2)z'' - λx^-(3/2)z' +(3/4)x^-(5/2)z
->ode
x^2{λ^2x^-(1/2)z'' - λx^-(3/2)z' +(3/4)x^-(5/2)z}
+2x{λx^-(1/2)z'-(1/2)x^-(3/2)z}
+λ^2x^2zx^-(1/2)=0
*x^(1/2)&ξ=λx->
ξ^2z''-ξz'+(3/4)z
+2ξz'-z
+ξ^2z=0
->
ξ^2z''+ξz'+{ξ^2 - 1/4}z=0
?@@
--
I seek not to know only answers, but to understand the questions.
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 123.193.214.165