Unravelling the Difference Between y' = sin(y) and y' = 2 + sin(y)

  • Context: Undergrad 
  • Thread starter Thread starter epheterson
  • Start date Start date
  • Tags Tags
    Difference
Click For Summary

Discussion Overview

The discussion revolves around the differences between the differential equations y' = sin(y) and y' = 2 + sin(y), focusing on their graphical representations and the implications of adding a constant to the equation. Participants explore the effects on slopes and equilibrium solutions, with references to visualizations created using Converge.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant seeks clarification on how adding a constant affects the graph of the differential equation, specifically noting the rotation and skewing of the graph.
  • Another participant observes that increasing the constant seems to increase the slope of the graph and notes the absence of equilibrium solutions beyond a certain point.
  • A third participant suggests that the perceived rotation is due to the steepening of slopes rather than a uniform transformation, emphasizing the non-uniformity of slope changes.
  • A later reply indicates that the initial confusion has been resolved, but does not elaborate on the specifics of the resolution.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the transformations affecting the graphs, with some suggesting rotation and others attributing the changes to slope increases. The discussion does not reach a consensus on the interpretation of these transformations.

Contextual Notes

There are references to specific behaviors of the differential equations, such as the presence of equilibrium solutions and the nature of slope changes, but these observations are not universally agreed upon and may depend on the interpretations of the participants.

epheterson
Messages
22
Reaction score
0
You might want to use converge to help me out with this one, or maybe you know off the top of your head.

I'm trying to determine how

y' = sin(y)

is different from

y' = 2 + sin(y)


I plotted them both in Converge and I don't understand how adding a two rotated and skewed the graph.

Can you explain to me however possible what is going on here?
 
Physics news on Phys.org
Or check out the attachment, I watched it while adding increments of .5 until I got up to y'=sin(y) + 2

It seems like every time you add a greater number, you increase the slope a little more. And past the point of y=sin(y) + 1, there are no more equilibrium solutions, it becomes monotonous.


Help?

I attached a word document with all the graphs from Converge
 

Attachments

Well, think about it.

It will rotate it because every slope becomes steeper, correct? Slopes that were 1 are now 3. That's a significant rotation.

It's looking translated is probably a coincidence. What really happened was an increasing of the slopes... and not a uniform one, at that.

So it's not really rotating or translating, although the periodicity of the field and the and the odd field transformation is making it look like that.
 
I understand completely now, thanks
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
4K
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 36 ·
2
Replies
36
Views
8K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 65 ·
3
Replies
65
Views
9K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 13 ·
Replies
13
Views
3K