How Is Curvature Calculated Using Vector Functions?

[chetzread]

Homework Statement

can someone explain how to turn the formula of curvature T'(t) / r'(t) into | r'(t) x r"(t) | / | (r't)^3 | ?

Homework Equations

The Attempt at a Solution

my working is in 317.jpgT'(t) / r'(t) <blockquote class="imgur-embed-pub" lang="en" data-id="a/q3t1U"><a href="//imgur.com/q3t1U"></a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>

[PLAIN]http://imgur.com/a/q3t1U[/B]

 

[BvU]

Can we merge this with the other thread ?

 

[berkeman]

@chetzread -- Please post this in your other thread. Thank you.