contestada

A hot air balloon rising vertically is tracked by an observer located 3 miles from the lift-off point. At a certain moment, the angle between the observer's line-of-sight and the horizontal is π3π3 , and it is changing at a rate of 0.1 rad/min. How fast is the balloon rising at this moment?

Respuesta :

Answer:

[tex]\frac{dy}{dt}=1.2\frac{mi}{min}[/tex]

Explanation:

We know that the tangent function relates the angle of the right triangle that forms the hot air balloon rising:

[tex]tan\theta=\frac{y}{x}\\y=xtan\theta(1)[/tex]

Differentiating (1) with respect to time, we get:

[tex]\frac{dy}{dt}=tan\theta\frac{dx}{dt}+xsec^{2}\theta\frac{d\theta}{dt}\\[/tex]

[tex]\frac{dx}{dt}=0[/tex] since x is a constant value. Replacing:

[tex]\frac{dy}{dt}=3mi(sec^{2}\frac{\pi}{3})0.1\frac{rad}{min}\\\frac{dy}{dt}=1.2\frac{mi}{min}[/tex]