Calculate the angle θ between the radiusvector of the point and the positive x axis (measured counterclockwise from the positive x axis, within the limits of −180◦ to +180◦ ). Answer in units of ◦ .

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.