Toronto Math Forum

MAT244--2019F => MAT244--Test & Quizzes => Quiz-3 => Topic started by: XueQiWang on October 14, 2019, 08:00:29 PM

Title: TUT0801 quiz3
Post by: XueQiWang on October 14, 2019, 08:00:29 PM
Q:Find the Wronskian of two solutions of the given differential equation without solving the equation.
x^2·y''+xy'+(x^2-v^2)y=0

A:
x^2·y''+xy'+(x^2-v^2)y=0
both side divided by x^2:  y''+y'/x+(x^2-v^2)y/x^2=0
such that: p(x)=1/x
W=ce^(-∫p(x)dx)=ce^(-∫(1/x)dx)=ce^(-ln(x)+c)=ce^(ln(1/x)+c)=cx^-1·e^c
therefore: W=c/x