Question

Find the unit tangent vector T(t) at the point with the given value of the parameter t.
r(t) = cos ti + 8tj + 3 sin 2tk, t = 0

Answer 1

what is r'(0) ?

Answer 2

10?

Answer 3

is it < 8/10 , 6/10 > ??

Answer 4

no, this R^3, what you got is R^2

Answer 5

well isn't it 4/5 j +3/5 k ???:S

Answer 6

r(t) = <cost, 8t, sin(2t)>

r'(t) = <-sint, 8, 2cos(2t) >

Answer 7

so, r'(0) = <0, 8, 2>

Answer 8

equation for a line
r(t) = t<0,8,2> + r(0)