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Hyperbolic Functions

 

 

 

 

         

 

Hyperbolic functions are analogs of the ordinary trigonometric, or circular, functions.

 

The points (cosh t, sinh t) define the right half of the equilateral hyperbola x² - y² = 1, in the same way that the points (cos t, sin t) define a circle.  Furthermore, cosh2t - sinh2t = 1. The hyperbolic functions are periodic with a complex period of 2πj. The parameter t is not a circular angle, but rather a hyperbolic angle.

    

The Hyperbolic Functions

    

sinh z = (ez - e-z) / 2 where z is a complex number, i.e., z = x + jy

cosh z = (ez + e-z) / 2 where z is a complex number, i.e., z = x + jy

tanh z = sinh z / cosh z

csch z = 1 / sinh z

sech z = 1 / cosh z

coth z = 1 / tanh z

    

Hyperbolic Functions in Relation to Trigonometric Functions

    

sinh z = -j sin jz

cosh z = cos jz

tanh z = -j tan jz

csch z = j csc jz

sech z = sec jz

coth z = j cot jz

    

See Also:  Trigonometric Functions; Math Used in ECE