Graphical construction of hyperbolic functions

TRANSMISSION line calculations requiring the use of complex hyperbolic functions are materially simplified through the construction and use of a chart from which both the complex hyperbolic sine and cosine values may be determined in either polar or complex-number form. The device is a polar rectangular chart combined with a specially constructed scale graduated in values of
${\epsilon^{a} \over 2}$
and
${\epsilon^{-a} \over 2}$
. The chart should be constructed with angles in circular radians and degrees which may be divided into convenient values. In constructing such a chart for practical use it may be convenient to employ heavy lines to denote each interval of 5 deg. and to subdivide these into degrees by fine lines. Ordinary cross-section paper having ten lines per inch is suitable for the rectangular chart.