calculus
posted by marlyn .
a hotair balloon rising srtaight up from level field is tracked by a range finder 5000 feet from the liftoff point. At the moment the range finder's elevation angle is 45 degrees (pie/4 radians), the angle is increasing at the rate of 0.14 radians per minute. how fast is the balloon rising at that moment?

altitude=5000*sinTheta
d altitude/dt= 5000*cosTheta* dTheta/dt