I know that $\cos x \leq (\sin x)/x \leq 1/(\cos x)$, but I need to prove this and I don't know how to do that. I've seen diagrams used to show the relationship, but can it be done without?
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It is the same question essentially. But the answers all use diagrams to prove and I am wondering if the above inequalities can be proven without to then be applied through squeeze theorem. – AdamK Jun 12 '17 at 13:26
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2It depends on how you defined $\sin x$. – velut luna Jun 12 '17 at 13:32
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Yes, what are you taking to be the definition of $\sin x$? Or are you asking this from the standpoint of someone who already knows the basic calculus facts about the trigonometric functions, such as $\sin' = \cos$ and $\cos' = -\sin$? – user49640 Jun 12 '17 at 13:48