A tourist at scenic Point Loma, California uses a telescope to track a boat approaching the shore. If the boat moves at a rate of 10
10
meters per second, and the lens of the telescope is 30
30
meters above water level, how fast is the angle of depression of the telescope (θ
θ
) changing when the boat is 150
150
meters from shore? Round any intermediate calculations to no less than six decimal places, and round your final answer to four decimal places.