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Domain of a logarithm
The domain of a logarithm is ( 0, ∞ ).
Explanation
Of course, negative numbers do not have a logarithm, because if you want to calculate loga(–2), you get a dislike: loga (–2) = x ⇒ ax = –2 . If a > 0, then ax must be positive for every value of x and ax = –2 is not possible.