Where do planes PRS and QRST intersect?

Passengers usually start to board their flights 1 hour before the scheduled take off time. the gate will be closed 15 minutes before the takeoff time. jack’s plane is scheduled to take off at 12: 05 a.m. if he arrives at the gate at 11: 45 p.m., can he board the flight?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Does the point (1, sqrt 7) lie on circle shown.