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Scilab help >> Elementary Functions > Trigonometry > asech


computes the element-wise inverse hyperbolic secant of the argument.

Calling Sequence

y = asech(x)



a real or complex array.


a real or complex array.


Computes the element-wise inverse hyperbolic secant of the argument. If the argument is real and have absolute value less than one the result is real.

The following equalities hold: asech(x) == acosh(1 ./ x) == %i*csgn(%i*(11 ./ x))*asec(x) == csgn(%i*(1 1 ./ x))*(%pi/2*(%i+acsch(%i*x))).


x=1 ./ [1 2 -2 sqrt(2) -sqrt(2) 2/sqrt(3) -2/sqrt(3) -1];

See Also

  • sech — computes the element-wise hyperbolic secant of the argument


  • Kahan, W., "Branch cuts for complex elementary functions, or, Much ado about nothing's sign bit", Proceedings of the joing IMA/SIAM conference on The State of the Art in Numerical Analysis, University of Birmingham, A. Iserles and M.J.D. Powell, eds, Clarendon Press, Oxford, 1987, 165-210.
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Last updated:
Tue Apr 02 17:36:21 CEST 2013