September 22nd, 2015, 09:44 PM  #1 
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  Second order difference equation
Sorry, need help to solve this urgently

September 22nd, 2015, 11:06 PM  #2 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,696 Thanks: 2681 Math Focus: Mainly analysis and algebra 
Without any knowledge of Mathcad, I suspect you want a loop structure to repeatedly calculate values using that formula until you hit $L_43$. It is possible to solve the sequence exactly for all $n$ quicker than I could write something in Mathcad, but since this is presumably a problem to get you familiar with the software, I'd do it that way. 
September 23rd, 2015, 01:39 AM  #3  
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  Quote:
 
September 23rd, 2015, 04:25 AM  #4 
Senior Member Joined: Dec 2013 From: some subspace Posts: 212 Thanks: 72 Math Focus: real analysis, vector analysis, numerical analysis, discrete mathematics 
For $\displaystyle n = 3:$ $\displaystyle L_3 = 2L_2  \tfrac{3}{2}L_1 = 2 \cdot \tfrac{1}{5}  \tfrac{3}{2} \cdot \tfrac{1}{10} = \tfrac{1}{10}$ Repeat until $\displaystyle n = 43$. 
September 23rd, 2015, 06:03 AM  #5 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,696 Thanks: 2681 Math Focus: Mainly analysis and algebra 
How about if I solve a different but similar problem and you apply the method to this one? Let $\displaystyle 8a_n = 2a_{n1} + 3a_{n2} \qquad a_0 = 0, \; a_1 = 1$ 
September 23rd, 2015, 07:22 AM  #6 
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  
September 23rd, 2015, 07:23 AM  #7  
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  Quote:
 
September 23rd, 2015, 07:49 AM  #8 
Math Team Joined: Dec 2013 From: Colombia Posts: 7,696 Thanks: 2681 Math Focus: Mainly analysis and algebra 
What do you not understand in the example I gave? This site is not intended as a place where you come to get your homework done for you. In the example I gave, we'd put $\displaystyle n = 43$ into the final equation to get $\displaystyle a_43$. 
September 23rd, 2015, 10:24 PM  #9  
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  Quote:
 
September 24th, 2015, 12:44 AM  #10 
Newbie Joined: Oct 2011 Posts: 6 Thanks: 0  Is it correct to do in this way?


Tags 
difference, equation, order 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
High order first derivative approximation with finite difference schemes  Genik  Applied Math  0  November 3rd, 2014 05:49 AM 
first order difference equation  sven77  Applied Math  0  May 22nd, 2013 04:56 AM 
The order of Backward difference method  raed  Applied Math  0  February 17th, 2012 11:15 AM 
Homogeneous Second?Order Difference Equations  scarymovie  Algebra  10  October 15th, 2008 07:18 PM 
first order difference equation  sven77  Calculus  0  December 31st, 1969 04:00 PM 