If n is any number, is the statement 2n + 1 always true? If so, why?

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Answer 1

If n is + or - infinity, then it is undefined (has no meaning), and therefore any expression using n would also be undefined.  If n = √-1 then it is an imaginary (also undefined) number, and n would equal i, so 2n+1 = 2i+1. Otherwise, any 2n+1 should be a valid and real value.