Infinitesimal rotation matrix: Difference between revisions

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Associated quantities: we can probably cut out one of these matrices. they take a lot of space, and I think readers can figure out how to remove the 1s from the diagonal of A
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===Associated quantities===
We can introduce here the associated ''[[infinitesimal rotation tensor]]'' <math>d\Phi(t) = A - I,</math> associated to this infinitesimal rotation matrix <math>A.</math> When it is divided by the time difference, this will yield the ''[[angular velocity tensor]]'':
 
: <math>
W = \frac{d\Phi(t)}{dt} = \begin{pmatrix}
0 & -d\phi_z(t) & d\phi_y(t) \\
0 d\phi_z(t) & 0 & -\omega_z(t) & & -d\phi_xomega_y(t) \\
-d\phi_yomega_z(t) & d0 & -\phi_xomega_x(t) & 0 \\
-\omega_y(t) & \omega_x(t) & 0 \\
\end{pmatrix}
</math>
Such that its associated rotation matrix is <math>A = I + d\Phi(t)</math>. When it is divided by the time difference, this will yield the ''[[angular velocity tensor]]'':
: <math>
W=\frac{d\Phi(t)}{dt} = \begin{pmatrix}
0 & -\omega_z(t) & \omega_y(t) \\
\omega_z(t) & 0 & -\omega_x(t) \\
-\omega_y(t) & \omega_x(t) & 0 \\
\end{pmatrix}
</math>