Some high school math that popped up today led me to this article about all the various transcendental functions. Love the diagram.
From the Scientific American blog in 2013:
10 Secret Trig Functions Your Math Teachers Never Taught You
Haversine? Exsecant? An introduction to obsolete trig functions and why we don’t use them anymore
Steven A. Guccione 
It’s much more important to understand the power-series of sin and cos and the connection to exp. Knowing these functions is wasting memory.
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