4 Elementary FunctionsHyperbolic Functions

§4.33 Maclaurin Series and Laurent Series

4.33.1 sinh⁡z=z+z33!+z55!+⋯,
4.33.2 cosh⁡z=1+z22!+z44!+⋯.
4.33.3 tanh⁡z=z−z33+215⁢z5−17315⁢z7+⋯+22⁢n⁢(22⁢n−1)⁢B2⁢n(2⁢n)!⁢z2⁢n−1+⋯,
|z|<12⁢π.

For B2⁢n see §24.2(i). For expansions that correspond to (4.19.4)–(4.19.9), change z to i⁢z and use (4.28.8)–(4.28.13).