4. A particle is moving along the curve r(t) = (t + t2.t 7 t2: 2?? + 1), where t 2 U. (a) (2 points) Does the particle pass through the point (6. 2, 4)? Why or why not? (b) (4 points) Determine at what time t the speed is x/ 22. (e) (4 points) At What point on the curve are the velocity and acceleration orthogonal