The amazing identity
for all , where is the gamma function. Equating coefficients of , , and gives some amazing identities for the hyperbolic secant.
The amazing identity
for all , where is the gamma function. Equating coefficients of , , and gives some amazing identities for the hyperbolic secant.
Weisstein, Eric W. "Ramanujan Cos/Cosh Identity." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/RamanujanCosCoshIdentity.html