The pendulum on a grandfather clock moves in a SINUSOIDAL fashion

The pendulum on a grandfather clock moves in a SINUSOIDAL fashion. The length of the pendulum is 31 inches at its lowest point. The pendulum is 1.5 feet from the floor. The pendulum begins to move at t1 so that the interior angle between t2 and t3 is 90 degrees. It takes .875 seconds for the pendulum to swing from t2 to t3. 

1. Write the sinusoidal equation that models the movement of the pendulum as a COSINE FUNCTION 

2. how high will the pendulum be in one hour

 3. what is the minimum and maximum height the pendulum will reach?