A hot air balloon rising vertically is tracked by an observer located 4 miles from the lift-off point. At a certain moment, the angle between the observer's line-of-sight and the horizontal is \frac{\pi}{3} , and it is changing at a rate of 0.1 rad/min. How fast is the balloon rising at this moment?

2 answers

Hey, I just did one very much like this. Your turn.
by the way,
d/dt (tan A) = sec^2 A * dA/dt
= (1/cos A)^2 * dA/dt