Simple looking 2nD ODE, with 2 sols, 0 and 3, confused on what to do now

  • Thread starter Thread starter mr_coffee
  • Start date Start date
  • Tags Tags
    Confused Ode
Click For Summary

Homework Help Overview

The discussion revolves around a second-order ordinary differential equation (ODE) given by y'' - 3y' = 0, with two initial conditions y(0) = 9 and y(1) = 7. The original poster expresses confusion regarding the requirements of the problem and the correctness of their constants A and B.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to find the function y as a function of t and has identified constants A and B but questions their correctness. Participants point out potential mistakes in the original poster's setup and calculations, particularly regarding the application of initial conditions.

Discussion Status

Participants are actively engaging with the original poster's confusion, offering corrections and clarifications. Some guidance has been provided regarding the constants and the initial conditions, but there is no explicit consensus on the next steps or final approach.

Contextual Notes

The original poster notes that both initial conditions are for y(x) and not for y'(x), which adds to their confusion. There is also a reference to a mistake in the formulation of the equation involving the constants.

mr_coffee
Messages
1,613
Reaction score
1
Hello everyone, I have time again to do more math so here i am!
I'm confused on what they want me to do here, I found A and B but they arn't pretty and i dind't even think they are right. Here is the problem, it has 2 inital conditions, both y(x) no y'(x) which also confused me.
ind y as a function of t if
y'' - 3y' = 0,
y(0) = 9, y(1) = 7 .
y(t) =

http://img51.imageshack.us/img51/566/lastscan0ei.jpg

THanks! any help would be great!
 
Last edited by a moderator:
Physics news on Phys.org
There is a mistake in your line [tex]7=Be^{3t}+A[/tex]. Can you see it?


EDIT: As so emphatically :wink: pointed out below, that is your mistake.
 
Last edited:
A and B are CONSTANTS! In y(1)= 7, you didn't set t= 1.
 
Ahh thank you everyone, I friggin' got it:
http://cwcsrv11.cwc.psu.edu/webwork2_files/tmp/equations/cf/6cde53ce8c93c51ddfe1e2f50b5e411.png
 
Last edited by a moderator:

Similar threads

Partial fraction decomposition with Laplace transformation in ODE
  • · Replies 9 ·
Replies
9
Views
3K
4th order RK to solve 2nd order ODE
  • · Replies 4 ·
Replies
4
Views
2K
Understanding the Chain Rule in Multivariable Calculus
  • · Replies 9 ·
Replies
9
Views
3K
Finding the homogenous solution of Var.Coeff. 2nd Order ODE
  • · Replies 3 ·
Replies
3
Views
2K
Solution verification of ODE using Frobenius' method
  • · Replies 3 ·
Replies
3
Views
2K
Stationary points classification using definiteness of the Lagrangian
  • · Replies 4 ·
Replies
4
Views
2K
Abel's Equation and Wronskian for find out y2
  • · Replies 1 ·
Replies
1
Views
2K
Homogeneous Diff. Eqn Finding Solution
  • · Replies 5 ·
Replies
5
Views
2K
Does it matter in which order I assign the values?
  • · Replies 11 ·
Replies
11
Views
2K
A numerical solution of a second order ODE
  • · Replies 2 ·
Replies
2
Views
1K