Let c be a curve w/parameterization r(t). show that the line integral of T dr equals the length of the curve where T is the unit tangent.

5 answers

am not even conversant with those .....i don,t know
Hmmm. Let me dig out my text on differential geometry. Meantime, try googling the topic in vector analysis.
Actually, just consider the definition of T.

Take a peek here, and it should be clear, since the arc length is just

∫ ds = ∫ |dr/dt| dt
oops: here is

http://math.oregonstate.edu/home/programs/undergrad/CalculusQuestStudyGuides/vcalc/arc/arc.html#alfunction
hmmm i got to write these down wow