Show how a sentence can be produced from a grammar (Dragon book 2.1)
$$\begin{align*}
S \Rightarrow &amp; SS* \\
  \Rightarrow &amp; SS+S* &amp; \text{(leftmost derivation )} \\
  \Rightarrow &amp; aS+S* \\
  \Rightarrow &amp; aa+S* \\
  \Rightarrow &amp; aa+a* \\
\end{align*}$$