E^x is greater than 1+x for nonzero real x
From specialfunctionswiki
Theorem
The following formula holds for nonzero $x \in \mathbb{R}$: $$e^x > 1+x,$$ where $e^x$ denotes the exponential.
Proof
References
- 1964: Milton Abramowitz and Irene A. Stegun: Handbook of mathematical functions ... (previous) ... (next): 4.2.30