Is following grammar has language which is inherently ambiguous?
Your grammar $$\begin{eqnarray}S &amp;\to&amp; aSb &amp;|&amp; A \\ A &amp;\to&amp; aaAb &amp;|&amp; \epsilon\end{eqnarray}$$ is indeed unambiguous. The production $S \to A$ must occur precisely once in any derivation, and the productions which precede it cannot be replaced with any productions which succeed it or vice versa.