Find the unit tangent vector T(t) at the given point on the curve. r(t) = + + 1, 2t - 6, (2, -4,9) tFind parametric equations for the tangent line to the curve with the given parametric equations at the specified point. x = t' + 1, y= 8vt, z= eth -t, (2, 8, 1) (x(t), y(t), z(t)) =