The lift-to-drag ratio is an indication of the effectiveness of an airfoil. \begin{array}{l}
L=\frac{1}{2} \rho C_{L} S V^{2} \\
D=\frac{1}{2} \rho C_{D} S V^{2}
\end{array} where, for a particular airfoil, the lift and drag coefficients versus angle ofattack a are given by \begin{array}{l}
C_{L}=\left(4.47 \times 10^{-5}\right) \alpha^{3}+\left(1.15 \times 10^{-3}\right) \alpha^{2}+\left(6.66 \times 10^{-2}\right) \alpha+\left(1.0 \times 10^{-1}\right) \\
C_{D}=\left(5.75 \times 10^{-6}\right) \alpha^{3}+\left(5.09 \times 10^{-4}\right) \alpha^{2}+\left(1.81 \times 10^{-4}\right) \alpha+\left(1.0 \times 10^{-2}\right)
\end{array} Using the first two equations, we see that the lift-to-drag ratio is givensimply by the ratio C₂/Cp. \frac{L}{D}=\frac{\frac{1}{2} \rho C_{L} S V^{2}}{\frac{1}{2} \rho C_{D} S V^{2}}=\frac{C_{L}}{C_{D}} a) Plot L/D versus a for -2≤ a ≤ 22⁰°.b) Determine the angle of attack that maximizes L/D.c) What is the value of maximum L/D?
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