Consider the flow at $M=2$ and zero incidence over the symmetric diamond shape airfoil $($shown in figure below$)$ using shock$-$expansion theory. $($Note: The lift is zero for a symmetric airfoil at zero incidence but the drag is not zero$)$

a$.$ Calculate the drag coefficient

b$.$ Calculate Pitot pressure reading if such a probe is mounted to side $3$ and facing the flow $($and parallel to the surface$)$ given that the freestream static pressure, $P_1,$ is $1$ bar.