Summary
We show visually that and discuss a generalization.
Acknowledgment
The author wishes to thank an anonymous reviewer and the Editor for helpful suggestions on an earlier draft of this note.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Notes on contributors
Roger B. Nelsen
ROGER NELSEN (MR Author ID: 237909) is a professor emeritus at Lewis & Clark College, where he taught mathematics and statistics for 40 years.