Question: Find the following limits

(a) \(\underset{x\to 3}{\mathop{\lim }}\,\frac{{{x}^{2}}-x-6}{x-3}\)

(b) \(\underset{\theta \to 0}{\mathop{\lim }}\,\frac{\sin \left( 3\theta \right)}{\sin \left( 5\theta \right)}\)