Domain of Mod-Trigo function ALLEN2017

Question

For existence of f(x) = , x lies in (take n  I)

(1)	[0, 2nπ]
(2)
(3)
(4)	None of these

how to solve such question? Pl give detailed explanation.

Always find difficult to solve Range and domain of such complex question.

Comments

@hs_yadav

$x\geq \infty$

is this even possible ??

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......  :)

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@ joshi_nitish Veteran

But given answer is option (B) ie. x lies in {  }

I don't know, How?