Trying to get this equation in terms of x

  • Thread starter Thread starter chazwozzler
  • Start date Start date
  • Tags Tags
    Terms
Click For Summary

Homework Help Overview

The discussion revolves around manipulating an equation to isolate the variable x on the left-hand side, specifically in terms of y, h, and t on the right-hand side. The equation provided is related to a numerical method known as the backward Euler method.

Discussion Character

  • Exploratory, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants express uncertainty about how to begin isolating x and question the feasibility of obtaining a solution in terms of elementary functions. There is mention of needing to apply numerical methods, such as the Newton-Raphson method, to find roots.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem and suggesting numerical approaches. Some guidance has been offered regarding the use of numerical root-finding algorithms, but there is no consensus on a specific method or solution yet.

Contextual Notes

Participants note the constraints of the problem, including the requirement to use the backward Euler method and the specific initial value problem being addressed. There is acknowledgment of the challenges associated with algorithmic approaches.

chazwozzler
Messages
4
Reaction score
0

Homework Statement


I need to have x on the LHS in terms of just y, h and t on the RHS:

Homework Equations


x = y + h(t2 - x2)sin(x)

The Attempt at a Solution


I really don't know where to begin. I'm pretty sure there'll need to be an arcsin somewhere. Is this even possible?
Thanks in advance!
 
Physics news on Phys.org
Oops, my mistake.
 
I think maybe I was oversimplifying things - it's a backward Euler method:

yn+1 = yn + h(tn+12 - yn+12)sin(yn+1)

so I think I have to get that just in terms of yn in order to get the algorithm.
 
Last edited:
If there's a general solution, it won't be in terms of elementary functions. If this is part of a grander numerical scheme, you can probably try to incorporate a numerical root-finding algorithm.
 
I don't know how to do that at all. The equation is

y' = (t2 - y2)siny,
y(0) = -1

and we're asked to use the backward Euler method to find approx. values for the IVP at t=0.1, 0.2, 0.3 and 0.4 with h=0.05.

I'm not very good at this algorithm thing..
 
You should look up the Newton-Raphson method for finding roots. You'll have to apply it at each step.
 
OK cheers
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 18 ·
Replies
18
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 20 ·
Replies
20
Views
3K
  • · Replies 43 ·
2
Replies
43
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 11 ·
Replies
11
Views
3K