So we are given T(t) = c'(t)/||c'(t)|| as well as ||T|| = 1(adsbygoogle = window.adsbygoogle || []).push({});

We also know T(t)dotT(t) = 1 and T'(t)dotT(t) = 0

The problem asks us to find T'(t)

I tried differentiating c'(t)/||c'(t)|| treating ||c'(t)|| as the square root of the dot product of c'(t) with itself. I used the product rule, chain rule, quotient rule, and ended up with some nasty terms, namely c'(t) dot c"(t).

I am pretty sure the answer we are looking for is T'(t) = c"(t). Therefore, if we can prove that T(t) = c'(t), then the answer T'(t) = c"(t) follows.

Please help! LOL Not being able to solve this has been bothering me big time!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Differentiation of Unit Tangent

**Physics Forums | Science Articles, Homework Help, Discussion**