Toronto Math Forum
Welcome,
Guest
. Please
login
or
register
.
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
News:
Home
Help
Search
Calendar
Login
Register
Toronto Math Forum
»
MAT244--2020F
»
MAT244--Lectures & Home Assignments
»
Chapter 2
»
Lec 0101 - 9/15 Question
« previous
next »
Print
Pages: [
1
]
Author
Topic: Lec 0101 - 9/15 Question (Read 4977 times)
Brandon Adiwinata
Newbie
Posts: 2
Karma: 0
Lec 0101 - 9/15 Question
«
on:
September 20, 2020, 06:16:36 PM »
I had a question from the lecture about the Methods for solving a differential equation. As indicated in the photo, how do we get u'(sqrt(t^2+1)) = t after plugging in y = u(sqrt(t^2+1)) into the original inhomogeneous equation?
«
Last Edit: September 20, 2020, 06:18:46 PM by Brandon Adiwinata
»
Logged
RunboZhang
Sr. Member
Posts: 51
Karma: 0
Re: Lec 0101 - 9/15 Question
«
Reply #1 on:
September 20, 2020, 07:12:43 PM »
Hi, I have plugged it in y and calculated the LHS. Computation is attached below.
Logged
Victor Ivrii
Administrator
Elder Member
Posts: 2607
Karma: 0
Re: Lec 0101 - 9/15 Question
«
Reply #2 on:
September 20, 2020, 07:49:47 PM »
One should remember that plugging $y=uy_1$ into inhimogeneous equation leaves $u'y_1$ in the left-hand expression. If you do not remember this, therefore you just do not understand the method of variations and you should reread previous slides
Logged
Print
Pages: [
1
]
« previous
next »
Toronto Math Forum
»
MAT244--2020F
»
MAT244--Lectures & Home Assignments
»
Chapter 2
»
Lec 0101 - 9/15 Question