AERODYNAMICS In designing airplanes, an important feature is the so-called drag factor; th...

AERODYNAMICS In designing airplanes, an important feature is the so-called drag factor; that is, the retarding force exerted on the plane by the air. One model measures drag by a function of the form

where v is the velocity of the plane and A and B are constants. Find the velocity (in terms of A and B) that minimizes F(v). Show that you have found the minimum rather than a maximum.