Given that F(t) =3ti+ 4sintk and G(t) =2costj. If a curve r (t ) is defined as r (t) = 3F (t)+6G(t), then find i) the unit tangent vector of the curve r (t) . ST BUM2123 18 APRIL 2022 00 PM (5 Marks) ii) the arc length of the curve r (t ) from point (0, 12, 0) to (3x, 6, 6V/3). (4 Marks)