i got r'(t) = <1, e^t(cos t - sin t) , e^t(sin t + cos t)>

r''(t) = <0, -2e^t(sin t), 2e^t(cos t)>

but i can't find any t which gives (0,0,1)?

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- March 27th 2012, 09:37 PMlinalg123r(t) = , t, e^t*cost, e^t*sint> find curvature at (0,0,1)
i got r'(t) = <1, e^t(cos t - sin t) , e^t(sin t + cos t)>

r''(t) = <0, -2e^t(sin t), 2e^t(cos t)>

but i can't find any t which gives (0,0,1)? - March 29th 2012, 01:38 PMHallsofIvyRe: r(t) = , t, e^t*cost, e^t*sint> find curvature at (0,0,1)
Yes, when t= 0, r= < 0, 1, 1> so the curve does NOT go through (0, 0, 1). I suspect the problem was supposed to say "at (0, 1, 1)".