Jacobian matrix determinant vanishes

In summary, the conversation discusses the meaning of a vanishing determinant of a Jacobian matrix in relation to a coordinate transformation. The speaker also raises the question of whether the coordinate transformation is good or bad and provides an explanation of a specific transformation using Euler angles. The conversation concludes with a potential error in the calculation resulting in a vanishing determinant.
  • #1
Demon117
165
1
What exactly does it mean when the determinant of a Jacobian matrix vanishes? Does that imply that the coordinate transformation is not a good one?

How do you know if you coordinate transformation is a good one or a bad one?
 
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  • #2
Let me explain further. This is the particular transformation I am looking at:

[itex]\left(
\begin{array}{c}
x(t) \\
y(t) \\
z(t)
\end{array}
\right)= R_{z}(\gamma) R_{x}(\beta) R_{z}(\alpha)\left(
\begin{array}{c}
x_o \\
y_o \\
z_o
\end{array}
\right)[/itex],

here, the vector [itex](x_{o},y_{o},z_{o})[/itex] is just the initial positions of small pieces of a solid cube, and the angles [itex]\alpha(t)[/itex],[itex]\beta(t)[/itex],[itex]\gamma(t)[/itex] are the Euler angles (all functions of time).

When I expand this out, and form the Jacobian matrix, it's determinant vanishes.
 
  • #3
Probably there is a mistake in your calculation. In the standard forms, the determinant of Rx , Ry and Rz all are 1.0 , for any angles. So is the determinant of their product.
 

FAQ: Jacobian matrix determinant vanishes

What is the Jacobian matrix determinant?

The Jacobian matrix determinant is a mathematical concept used in multivariable calculus to determine the change in volume or area under a transformation. It is calculated by taking the partial derivatives of a set of variables and arranging them into a square matrix, where the determinant represents the scale factor of the transformation.

Why does the Jacobian matrix determinant vanish?

The Jacobian matrix determinant vanishes when there is a point or region in the transformation where the scale factor becomes zero. This means that the transformation is not invertible at that point, and the volume or area cannot be accurately calculated. This can happen when there is a singularity or critical point in the transformation.

How is the Jacobian matrix determinant used in real-world applications?

The Jacobian matrix determinant is used in various fields such as physics, engineering, and computer graphics to calculate the change in volume or area under a transformation. It is also used in optimization problems and in determining the stability of a system in dynamical systems.

Are there any alternative methods to calculate the Jacobian matrix determinant?

Yes, there are alternative methods such as using the inverse matrix or calculating the determinant using the cross product of partial derivatives. These methods may be more efficient in certain situations, but the traditional method of calculating the determinant using the partial derivatives is the most commonly used.

Can the Jacobian matrix determinant be negative?

Yes, the Jacobian matrix determinant can be negative, positive, or zero depending on the transformation and the point being evaluated. A negative determinant indicates a change in orientation or direction, while a positive determinant indicates a consistent change in orientation. A zero determinant, as mentioned earlier, indicates a point where the transformation is not invertible.

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