Sketching Psi as a function of x

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Discussion Overview

The discussion revolves around the challenges of sketching a psi function in quantum mechanics, particularly when the function does not exhibit sinusoidal behavior. Participants explore the characteristics of wave functions, the mathematical representation of these functions, and the prerequisites for understanding them, such as calculus knowledge.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions how to sketch a psi function without sinusoidal components, noting variability in the function's appearance.
  • Another participant emphasizes the need for specific references or descriptions of the wave function in question to provide meaningful assistance.
  • Some participants suggest that the function may consist of straight lines rather than curves, and recommend evaluating the function at specific points (x=0, x=a, x=b) to understand its behavior.
  • A mathematical representation of a linear segment of the psi function is proposed, indicating that the region can be expressed as a linear equation.
  • There is a suggestion that the original poster (OP) may be confused and has taken examples from the internet without a clear understanding of the problem they are trying to solve.
  • One participant mentions that a lack of calculus knowledge may hinder the OP's ability to graph functions, while also providing a link to a plotting tool as a potential resource.
  • Several participants discuss formatting issues related to posting equations and text, indicating a preference for direct text input over images.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the psi function, with some asserting it consists of straight lines while others suggest there may be curving involved. The discussion remains unresolved regarding the OP's specific problem and the appropriate approach to sketching the function.

Contextual Notes

There are indications that the discussion is influenced by the OP's lack of calculus knowledge, which may limit their understanding of the mathematical concepts involved in sketching the psi function.

tsumugori
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How do i sketch a psi function when there is no sinus or cosinus i see sometimes its curving but sometimes its directly going down when reaching the top whats the decisive factor here to sketch a graph.
 
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To sketch any function you have to have some knowledge about it. What particular wave function are you interested in? Can you give a reference? Can you describe the particular physical situation?
 
A reference would be especially helpful. You said "I see sometimes ...". So a link to one of those would be best.
 
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tsumugori said:
The first problem literally provides the instructions to draw the wave function. The second image is missing information. It would be better if you provide full citations of the problem you are truly interested in.
 
tsumugori said:
How do i sketch a psi function when there is no sinus or cosinus i see sometimes its curving but sometimes its directly going down when reaching the top whats the decisive factor here to sketch a graph.
tsumugori said:

Your description seems wrong. There is no "curving". The function pieces together straight lines. Evaluate the function at x=0, x=a, and x=b and see how far you can get from there.

PS. This looks like a homework-type of problem. For those, there is a specific format and we are only allowed to give hints and guidance on your work.
 
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tsumugori said:
Does it help to notice that the ##a\le x \le b## region can be written as $$\Psi = \frac{A}{a-b}x+\frac{Ab}{b-a}$$ which is the standard equation of a line ##y=mx+b##

Hopefully the other two regions are even easier to recognize.
 
FactChecker said:
Your description seems wrong. There is no "curving". The function pieces together straight lines. Evaluate the function at x=0, x=a, and x=b and see how far you can get from there.

PS. This looks like a homework-type of problem. For those, there is a specific format and we are only allowed to give hints and guidance on your work.
Dale said:
Does it help to notice that the ##a\le x \le b## region can be written as $$\Psi = \frac{A}{a-b}x+\frac{Ab}{b-a}$$ which is the standard equation of a line ##y=mx+b##

Hopefully the other two regions are even easier to recognize.
I do not think that this is what OP is trying to solve, he just took random examples from the internet. OP please clarify.
 
tsumugori said:
How do i sketch a psi function when there is no sinus or cosinus i see sometimes its curving but sometimes its directly going down when reaching the top whats the decisive factor here to sketch a graph.
Before studying quantum mechanics, you first need to study calculus.

But even if you don't know calculus, you can plot any function with this:
https://www.wolframalpha.com/examples/mathematics/plotting-and-graphics
 
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  • #10
Screenshot 2024-11-23 014724.png
Screenshot 2024-11-23 014626.png
Screenshot 2024-11-23 014746.png
Screenshot 2024-11-23 014809.png

 
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  • #11
i hope it helps a bit
 
  • #12
@aine, images of text and equations are not acceptable here. Please type text directly into your post and use the PF LaTeX feature for equations. There is a "LaTeX Guide" link at the lower left of the window you use to type posts.
 
  • #13
The fake notebook font is pretty. What is the name of the font?
 
Last edited:
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  • #14
i just took these form the questions i saw which include sketching psi ( im studying for exam) my problem here was i cant graph a function even tho i can solve the rest of its like demystifier said its lack of calculus information problem i guess thanks for the replies.
 
  • #15
Dale said:
The fake notebook font is pretty. What is the name of the font?
Gloria Hallelujah font --- took me forever but found it
 
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  • #16
Jobean123 said:
Gloria Hallelujah font --- took me forever but found it
Awesome! That is not something I thought I would learn on PF, but I have to say I am pretty happy to have learned it. I may use that font for woodworking.
 
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