Find the curvature of the vector at the point

Find the curvature of
r(t) = < 3t, t^2, t^3 >
at the point
(3, 1, 1).

r'(t) = <3, 2t, 3t²> and r''(t) = <0, 2, 6t>.

The point (3, 1, 1) corresponds to t = 1.

r'(1) = <3, 2, 3>, r''(1) = <0, 2, 6>

r'(1) x r''(1) = <6, -18, 6>, ||r'(1) x r''(1)|| = 6√(11), and ||r'(1)|| = √(22)

The curvature at t = 1 is

k = ||r'(1) x r''(1)||/||r'(1)||^3 = 3/(11√2).