I forgot what the formula for this is.

  • Context: Undergrad 
  • Thread starter Thread starter flyingpig
  • Start date Start date
  • Tags Tags
    Formula
Click For Summary

Discussion Overview

The discussion revolves around the mathematical concept of rotating a function about the x-axis using matrices and the implications of such transformations. Participants explore the relationship between rotation matrices and functions, particularly in the context of specific angles.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant inquires about the formula for rotating a function f(x) about the x-axis by an angle phi, expressing uncertainty about using matrices for functions.
  • Another participant suggests looking at rotation matrices and provides links to Wikipedia articles for reference.
  • There is a mention of SO(n) and a question about whether Euler's formula could apply, although it is noted that Euler's formula pertains to complex numbers.
  • A participant questions the feasibility of rotating a function, suggesting that a 90-degree rotation may result in a non-function.
  • Another participant proposes that the function would need to be considered in three dimensions, indicating the existence of multiple components (fx, fy, fz) for a complete representation.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of rotation matrices to functions, with some questioning the validity of such transformations and others suggesting that a three-dimensional approach may be necessary. No consensus is reached on how to properly define the rotation of a function.

Contextual Notes

Participants highlight the potential limitations of applying rotation matrices to functions, particularly regarding the definition of a function after transformation. There is also an acknowledgment of the complexity involved in representing functions in three dimensions.

flyingpig
Messages
2,574
Reaction score
1
If I give you a function f(x) (cartesian) and I ask you to rotate it about the x-axis (counterclockwise) by an angle phi, what is the new function formula?

I remember I did this with matrices, but I can't remember the one for functions. For convenience, let angle phi be 0, pi/2, 3pi/2, and 2pi.

I am guessing 0 would remain the same. I just don't know how to use matrices on functions.

Does anyone understand my question?
 
Physics news on Phys.org
There's obviously [itex]SO(n)[/itex] but that's matrices.

Doesn't Euler's formula do that same thing?

[itex]e^{i\theta} = cos\theta + isin\theta[/itex]

EDIT: Euler's formula is only for complex numbers.
 
Yes, but for functions. Is there no equivalence? I kinda had something like this for conics
 
Kevin_Axion said:
There's obviously [itex]SO(n)[/itex] but that's matrices.

Doesn't Euler's formula do that same thing?

[itex]e^{i\theta} = cos\theta + isin\theta[/itex]

EDIT: Euler's formula is only for complex numbers.

No real numbers please
 
Hhhmmm...if you have a set of points, I can see being rotated with a transformation matrix...but a function? If you have a function f(x) and you "rotate" it 90 degrees...chances are it will stop being a function!...at least, in the sense of the new fnew(x) = trans(forig(x))
 

Similar threads

  • · Replies 26 ·
Replies
26
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
1
Views
1K
Replies
31
Views
3K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K