A proof which can be accomplished using only real numbers (i.e., real analysis instead of complex analysis; Hoffman 1998, pp. 92-93).
Elementary Proof
See also
Elementary Methods, Elementary Number Theory, ProofExplore with Wolfram|Alpha
References
Hoffman, P. The Man Who Loved Only Numbers: The Story of Paul Erdős and the Search for Mathematical Truth. New York: Hyperion, 1998.Wells, D. The Penguin Dictionary of Curious and Interesting Numbers. Middlesex, England: Penguin Books, p. 22, 1986.Referenced on Wolfram|Alpha
Elementary ProofCite this as:
Weisstein, Eric W. "Elementary Proof." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ElementaryProof.html