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►►►Figure 4.29.6: Principal values of and .
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§4.29(ii) Complex Arguments
►The conformal mapping is obtainable from Figure 4.15.7 by rotating both the -plane and the -plane through an angle , compare (4.28.8).
►The surfaces for the complex hyperbolic and inverse hyperbolic functions are similar to the surfaces depicted in §4.15(iii) for the trigonometric and inverse trigonometric functions.
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►As a consequence, many properties of the hyperbolic functions follow immediately from the corresponding properties of the trigonometric functions.
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Periodicity and Zeros
►The functions and have period , and has period .
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►The main purpose of the present chapter is to extend these definitions and properties to complex arguments .
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►; the hyperbolic trigonometric (or just hyperbolic) functions , , , , , ; the inverse hyperbolic functions , , etc.
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