regular smooth curve - Penn Math
regular smooth curve - Penn Math
regular smooth curve - Penn Math
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Let �: I � R 3 be a <strong>regular</strong> (<strong>smooth</strong>) <strong>curve</strong>.<br />
Then the arc length along � , starting from some<br />
point �(t0) , is given by<br />
t<br />
s(t) = �to |�'(t)| dt .<br />
Note that s'(t) = |�'(t)| � 0 , so we can invert this<br />
function to obtain t = t(s) .<br />
Then �(s) = �(t(s)) is a reparametrization of our <strong>curve</strong>,<br />
and |�'(s)| = 1.<br />
We will say that � is parametrized by arc length.<br />
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