Consider the helix r(t) = <cost, sint, t> for [-inf, inf]. Find all points on the helix at which r and r' are orthogonal

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- Oct 17th 2012, 07:41 PMjessicadowningFind the points where orthogonal
Consider the helix r(t) = <cost, sint, t> for [-inf, inf]. Find all points on the helix at which r and r' are orthogonal

- Oct 17th 2012, 07:53 PMTheEmptySetRe: Find the points where orthogonal
Well if we take the derivative we get

$\displaystyle r'(t)=<-\sin(t), \cos(t), 1>$

Two vectors are orthongal is their dot product is equal to zero, so....

Can you finish from here?

By the way how is Corvallis? I miss it alot. I would kill for Tarn Tip Thai about now. - Oct 17th 2012, 07:53 PMchiroRe: Find the points where orthogonal
Hey jessicadowning.

Can you compute r'(t)? When are two vectors orthogonal? (Hint: it has something to do with something being 0) - Oct 17th 2012, 08:04 PMjessicadowningRe: Find the points where orthogonal
Yeah, I got it from there, thanks so much!

And Corvallis is great, I'm loving it so far! (I'm a freshman, lol)

I haven't heard of Tarn Tip Thai, but it sounds good, I'll have to try it! :) - Oct 17th 2012, 08:11 PMTheEmptySetRe: Find the points where orthogonal