Mathematics

Problem

A radar station at ground level tracks an airplane flying horizontally at a constant altitude of

3\text{ km}

. If the angle of elevation to the plane is

0.5\text{ rad}

and decreasing at

0.02\text{ rad/min}

, what is the rate at which the horizontal distance between the radar and the plane is changing at that instant? a)

0.23\text{ km/min}

-0.26\text{ km/min}

0.26\text{ km/min}

0.18\text{ km/min}