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Hyperbolic Functions

$$\small \sinh(x) = \frac{e^x - e^{-x}}{2}, \cosh(x) = \frac{e^x + e^{-x}}{2}, \tanh(x) = \frac{e^x - e^{-x}}{e^x + e^{-x}}$$

Where

  • \(e\) is Euler’s number ~= 2.71828, and
  • \(i\) is the imaginary unit, \(\sqrt{-1}\)

Complex trig definitions #

The hyperbolic functions can be defined in terms of the trig functions with complex arguments:

  • \(\sinh(x) = -i \sin(ix)\)
  • \(\cosh(x) = \cos(ix)\)
  • \(\tanh(x) = -i \tan(ix)\)

Sources #