Unit tangent vector

krazydog

New member
Joined
Oct 25, 2011
Messages
14
I am trying to find the unit tangent vector T(t)
Heres the problem


\(\displaystyle r(t) = ti + \frac{1}{t}j, t = 1\)


\(\displaystyle v(t) = i - \frac {1}{t^2} j\)

then

\(\displaystyle a(t) = \frac {2}{t^3} j\)

I think the magnitude is:

\(\displaystyle ||v(t)|| = \sqrt \frac{2} {t^4} j\)

then the solutions manual has this:



\(\displaystyle T(t) = \frac {v(t)}{ || v(t) ||} = \frac{t^2} {\sqrt{ t^4 + 1}} (i - \frac{ 1}{t^2}j )\)

I am not sure how they are getting this.
Can someone help me with the steps? I would appreciate this!!
 
\(\displaystyle \sqrt{1^{2} + \left(-\frac{1}{t^{2}}\right)^{2}}\)

Not quite what you have for the Magnitude.
 
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