Question

I think there is a typo
the first line says || alpha(t)||= 1

Answer 1

werowletu

Answer 2

here is the link
http://math.creighton.edu/nielsen/Calculus_III_Fall_2011/Mathematica%20Documents/Curve_EGs.pdf

Answer 3

∞aHtL¥=1

Answer 4

if the magnitude of a curve at time t is 1, it must be a unit circle :O