Exponential of Real Number is Strictly Positive/Proof 3

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Theorem

Let $x$ be a real number.

Let $\exp$ denote the (real) exponential function.


Then:

$\forall x \in \R : \exp x > 0$


Proof

This proof assumes the definition of $\exp x$ as the unique continuous extension of $e^x$.


Since $e > 0$, the result follows immediately from Power of Positive Real Number is Positive over Rationals.

$\blacksquare$