Possible typo in a PDF I am reading

[Richard Baker]

https://www.researchgate.net/publication/242501702_The_Mathematical_Description_of_Shape_and_Form

On page 16, there appears to be a typo on formula (2.13).  Should there be a dot above psi?  So curvature should equal a derivative of the angle with respect to arc length.  

Thank you.

[joigus]

1 hour ago, Richard Baker said:

https://www.researchgate.net/publication/242501702_The_Mathematical_Description_of_Shape_and_Form

On page 16, there appears to be a typo on formula (2.13).  Should there be a dot above psi?  So curvature should equal a derivative of the angle with respect to arc length.  

Thank you.

Yes, the next line after the equation says exactly that: "where the dot means...". It should be,

\[ \kappa = \dot{\psi} \]

'dot' to represent the derivative by the length of arc is traditional in differential geometry.

[Richard Baker]

How do you get the specialized symbols?

I will relay this to him.  Thank you.

[joigus]

On 8/11/2021 at 6:57 PM, Richard Baker said:

How do you get the specialized symbols?

I will relay this to him.  Thank you.

That's LaTeX.

https://www.scienceforums.net/forum/99-the-sandbox/