
Differential Equations Ordinary and Partial Differential Equations Math Forum 
 LinkBack  Thread Tools  Display Modes 
June 29th, 2018, 11:34 AM  #1 
Senior Member Joined: Dec 2015 From: Earth Posts: 238 Thanks: 27  Simple short question on differentials
Does the equation below have an integrating factor? If not, why? If yes, why? $\displaystyle X''+p(x)X'+q(x)X=f(x)$ Last edited by skipjack; June 29th, 2018 at 10:20 PM. 
June 29th, 2018, 11:56 AM  #2 
Senior Member Joined: Sep 2016 From: USA Posts: 437 Thanks: 247 Math Focus: Dynamical systems, analytic function theory, numerics 
Answer is yes because it is a linear equation and every linear equation has a solution by integrating factor method. Sometimes this is called the variation of constants method when applied to higher order equations but they are exactly the same method.

June 29th, 2018, 01:27 PM  #3 
Global Moderator Joined: May 2007 Posts: 6,582 Thanks: 610 
Integrating factors can be used in general for first order equations. For higher order some work will be required.


Tags 
differentials, question, short, simple 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
short regular expression question  Lobinho  Computer Science  0  November 11th, 2015 12:06 PM 
Please help, I cannot figure this out, very short question.  Nmbvc0  Algebra  7  March 6th, 2013 07:49 AM 
A calculus question with limits and differentials  cacophonyjm  Calculus  2  March 20th, 2012 10:17 PM 
Urgent! question about differentials  studentx  Applied Math  2  November 19th, 2011 12:54 AM 
Please Help, I cannot figure this out, very short question.  Nmbvc0  Calculus  0  December 31st, 1969 04:00 PM 