



 
Hi Ameen, Since the domains of $\sin(x)$ and $\cos(x)$ are the entire real line the only possible real number $x$ not in the domain of \[f(x) = \frac{\cos(2x)}{\sin(x)  2}\] is an $x$ that makes $\sin(x)  2 = 0.$ For what value of $x$ is $\sin(x)  2 = 0?$ Penny  


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