3. Write a formula for the thrust required to keep an aircraft in steady flight. The drag coefficient of the aircraft is given by: CD = A + B C₁² A and B are known constants. Drag and Lift coefficients are: CD=D/ (1/2 pa U。。² S) and CL=L/ (1/2 pa U。。² S) a) Write an equation for thrust in terms of the weight of the aircraft (W), the flight speed (U..) the ambient air density pa the wing planform area (S), and A and B. b) Sketch a plot (using your pen, if you wish or use Exel, etc.) showing the required thrust on the vertical axis, versus the flight speed on the horizontal axis. c) Explain in a few sentences why large thrust is required at both very low flight speeds and at very high flight speeds.