asec
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Name

asec — computes the element-wise inverse secant of the argument.

Calling Sequence

y = asec(x)

Parameters

x

Real or complex array.

y

Real or complex array.

Description

Computes the element-wise inverse secant of the argument. For real argument with absolute value greater than 1 the result is real.

The following equalities hold: asec(z) = -acsc(-z) = asin(1/z) = %pi/2-asec(x) = %i*acsch(%i*z)

Examples

 
x=[1 2 -2 sqrt(2) -sqrt(2) 2/sqrt(3) -2/sqrt(3) -1];
asec(x)/%pi

See Also

sec, asecd

References

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.

Authors

Serge Steer, INRIA
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