4 Elementary FunctionsHyperbolic Functions

§4.34 Derivatives and Differential Equations

4.34.1 ddz⁡sinh⁡z =cosh⁡z,
4.34.2 ddz⁡cosh⁡z =sinh⁡z,
4.34.3 ddz⁡tanh⁡z =sech2⁡z,
4.34.4 ddz⁡csch⁡z =−csch⁡z⁢coth⁡z,
4.34.5 ddz⁡sech⁡z =−sech⁡z⁢tanh⁡z,
4.34.6 ddz⁡coth⁡z =−csch2⁡z.

With a≠0, the general solutions of the differential equations

4.34.7 d2wdz2−a2⁢w =0,
4.34.8 (dwdz)2−a2⁢w2 =1,
4.34.9 (dwdz)2−a2⁢w2 =−1,
4.34.10 dwdz+a2⁢w2 =1,

are respectively

4.34.11 w =A⁢cosh⁡(a⁢z)+B⁢sinh⁡(a⁢z),
4.34.12 w =(1/a)⁢sinh⁡(a⁢z+c),
4.34.13 w =(1/a)⁢cosh⁡(a⁢z+c),
4.34.14 w =(1/a)⁢coth⁡(a⁢z+c),

where A,B,c are arbitrary constants.

For other differential equations see Kamke (1977, pp. 289–400).