Add exact formulation of interaction efficiency

ift6065c-microtargetome-analysis-assignment.md

@@ -17,7 +17,11 @@ a idealized setup.
 [ES]_{max} &= \frac{Z - \sqrt{Z^2 - 4 [E]_0[S]_0}}{2} & Z = K_m + [E]_0 + [S]_0
 \end{align}
 
-The efficiency is given by the ratio $[ES]/[ES]_{max}$.
+The efficiency notes $\eta_{[ES]}$ is given by the ratio $[ES]/[ES]_{max}$, thus
+
+\begin{align}
+\eta_{[ES]} &= \frac{2[ES]}{Z - \sqrt{Z^2 - 4 [E]_0[S]_0}} & Z = K_m + [E]_0 + [S]_0
+\end{align}
 
 \begin{questions}
 \question[5] Using NumPy routines, compute this efficiency for each