What is the derivative of a skew symmetric matrix?

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Homework Help Overview

The discussion revolves around proving that the derivative of a rotation matrix is a skew symmetric matrix multiplied by that rotation matrix, specifically in the context of Rodrigues' formula.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants explore the relationship between skew symmetric matrices and rotation matrices, with one participant attempting to apply the product rule to the derivative of the skew matrix. Questions arise regarding the parameters with respect to which the derivative is taken.

Discussion Status

Participants are actively discussing the formulation of the problem and the necessary parameters for differentiation. There is an ongoing exploration of the mathematical expressions involved, particularly the Rodrigues formula, but no consensus has been reached on the derivative's specifics.

Contextual Notes

One participant notes a potential issue with the representation of the skew symmetric matrix in their posts, which may affect clarity. The discussion also highlights the need for precise definitions and assumptions regarding the parameters involved in the differentiation process.

Musa00098

Homework Statement


Need to prove that the derivative of a rotation matrix is a skew symmetric matrix muktiplied by that rotation matrix. Specifically applying it on the Rodrigues’ formula.

Homework Equations

The Attempt at a Solution


I have shown that the cubed of the skew symmetric matrix is equal to the opposite of the skew symmetric matrix. I;m supposed to use this to finish the proof of the above problem. But I get to a point where I have something like the skew matrix multiplied by sin, so I'm thinking of just doing the product rule here but I'm unsure what the derivative of the skew matrix is. I went with "derivative of skew symmetric matrix is a skew symmetric matrix" but that didn't work out
 
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Derivative with respect to what? In order to have a derivative at all there must be one or more parameters that the object depends on.
 
So the rotation matrix is R, rotated about an arbritrary axis k, and the rotation angle is theta. The derivative is with respect to theta. Here let me write the Rodrigues formula the best I can on my phone:

R(k, theta) = I + {u}*sin(theta) + {u}^2 * (1-cos(theta))

Where I is the identity matrix and {u} is a skew symmetric matrix, which would have the form of something like this:

{u} = [0 -z y; z 0 -x; -y x 0]

So I need to take the derivative of the rotation matrix R and show that it equals {u}*R
 
Last edited by a moderator:
Weird, apparently (open bracket) u (close bracket) isn't showing up in my post, so I switched it to {u}
 
Musa00098 said:
Weird, apparently (open bracket) u (close bracket) isn't showing up in my post, so I switched it to {u}
This is because is interpreted by a browser as the starting underscore tag -- the browser consumes this special character, which is why it seemed to disappear, and also why so much of your post was underscored.

I fixed your previous post, but you should take a look at it again to see if it says what you meant.
 

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