For the trajectory 7 (t) = find the length of the trajectory on the interval Osts In2. O A. 2cos2 O B. 215 OC. 3 OD. 213 Find an equation of the plane passing through the points P (5,3,1) , Q(1,3, -5), R(-1,3,1) . O A. 2 (x- 5) +3(y-3) +4(z-1) = 0 O B. 3 (x- 5) +5(y-3) +4(z-1) = 0 O c. y = 3 OD. Z = 1