An aircraft is fying at a constant altitude with a constant speed of 600 miles per hour. An antiaircraft
missile is fired on a straight line perpendicular to the flight path of the aircraft so that it will
hit the aircraft at a point P (see the accompanying figure). At the instant the aircraft is 2 mi
from the impact point P the missile is 4 miles from P and flying at 1200 miles per hour. At that instant.
how rapidly is the distance between inissile and aircraft decreasing?
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