AllExperts > Differential Equations 
Search      
Differential Equations
Volunteer
Answers to thousands of questions
 Home · More Differential Equations Questions · Answer Library  · Encyclopedia ·
More Differential Equations Answers
Question Library

Ask a question about Differential Equations
Volunteer
Experts of the Month
Expert Login

Awards

About Us
Tell friends
Link to Us
Disclaimer

 
 
 
 
About Abe Mantell
Expertise
Hello, I am a college professor of mathematics and regularly teach all levels from elementary mathematics through differential equations, and would be happy to assist anyone with such questions!

Experience
Over 15 years teaching at the college level.

Organizations
NCTM, NYSMATYC, AMATYC, MAA, NYSUT, AFT.

Education/Credentials
B.S. in Mathematics from Rensselaer Polytechnic Institute
M.S. (and A.B.D.) in Applied Mathematics from SUNY @ Stony Brook

 
   

You are here:  Experts > Science > Mathematics > Differential Equations > Differential Equation, Solutions

Differential Equations - Differential Equation, Solutions


Expert: Abe Mantell - 6/6/2009

Question
1.Determine the singular points of the given differential equation, then classify each singular point as regular or irregular.

(x^2)(x+1)y'' + ((x^2)-1)y' - y = 0

2. Solve xy'' - xy' + y = 0

3. x=0 is a regular singular point of the differential equation:
(x^2 + x - 6)y'' - (x+3)y' + (x-2)y = 0,
Determine the form of the solution of the differential equation.

Answer
1. Re-written as: y'' + (x^2-1)/(x^2(x+1)) y' - y/(x^2(x+1)) = 0
.  Singular points where x^2(x+1)=0...thus x=0 and x=-1 are singular pts.
.  Since lim (as x->0) x[(x^2-1)/(x^2(x+1))] DNE, x=0 is an irregular
.  singular pt.  Since lim (as x->-1) (x+1)[(x^2-1)/(x^2(x+1))]=0
.  and lim (as x->-1) (x+1)^2[(x^2-1)/(x^2(x+1))]=0, x=-1 is a regular
.  singular pt.

2. The solution works out to be:
.  y(x)=C1*x+C2*(-x*ln(x)+1+x-(1/2)*x^2-(1/12)*x^3-(1/72)*x^4-
       (1/480)*x^5-(1/3600)*x^6-(1/30240)*x^7-(1/282240)*x^8+...)

3. The solutions works out to be:
.  y(x) = y(0)+y'(0)*x+(-(1/4)*y'(0)-(1/6)*y(0))*x^2+(-(1/18)*y'(0)+
(5/108)*y(0))*x^3+((5/216)*y'(0)+(7/2592)*y(0))*x^4+(-(11/4320)*y'(0)
-(13/12960)*y(0))*x^5+((61/155520)*y'(0)+(149/466560)*y(0))*x^6+
(-(17/816480)*y'(0)-(253/9797760)*y(0))*x^7+((439/26127360)*y'(0)+
(2557/156764160)*y(0))*x^8+...

Abe


Add to this Answer   Ask a Question


 
User Agreement | Privacy Policy | Kids' Privacy Policy | Help
Copyright  © 2008 About, Inc. AllExperts, AllExperts.com, and About.com are registered trademarks of About, Inc. All rights reserved.