Talk:Power Series Expansion for Hyperbolic Secant Function

Is the proof for this not some form of circular reasoning? If you look at The euler numbers they are defined by the hyperbolic secant function but if you look at this proof they are defined by the euler numbers.

-Mosh (talk) 20:23, 11 October 2019 (EDT)

Heh! Well spotted. If you have a mind to, either add a further definition of either Euler numbers, or derive this result in another way. Or use whatever technique to break out of the circle. It's all yours if you want, do what you can. --prime mover (talk) 20:26, 11 October 2019 (EDT)