Calculus
posted by Reonea .
A hot air balloon rising vertically is tracked by an observer located 3 miles from the liftoff point. At a certain moment, the angle between the observer's lineofsight and the horizontal is pi/5 , and it is changing at a rate of 0.1 rad/min. How fast is the balloon rising at this moment?
______ miles/min

tanTheta=h/x
take derivative
sec^2 theta dtheta/dt= 1/x dh/dt
find dh/dt x= 3 miles theta= pi/5,dtheta/dt= .1rad/min