Find the curve's unit tangent vector. Also, find the length of the indicated portion of the curve. r(t) = 8ti + 1+ 3/2 k , Ost5 57 3 ..... The curve's unit tangent vector is i + + (1) K. (Type exact answers, using radicals as needed.) The length of the indicated portion of the curve is units. (Type an integer or a simplified fraction.)