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33 lines
678 B
Plaintext
33 lines
678 B
Plaintext
NAME
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asech - inverse hyperbolic secant
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SYNOPSIS
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asech(x [,eps])
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TYPES
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x real, 0 < x <= 1
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eps nonzero real, defaults to epsilon()
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return real
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DESCRIPTION
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Returns the asech of x to a multiple of eps with error less in
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absolute value than .75 * eps.
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asech(x) is the real number v for which sech(v) = x. It is given by
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asech(x) = ln((1 + sqrt(1 - x^2))/x)
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EXAMPLE
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> print asech(.5,1e-5), asech(.5,1e-10), asech(.5,1e-15), asech(.5,1e-20)
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1.31696 1.3169578969 1.316957896924817 1.31695789692481670862
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LIMITS
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none
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LIBRARY
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NUMBER *qasech(NUMBER *x, NUMBER *eps)
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SEE ALSO
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asinh, acosh, atanh, acsch, acoth, epsilon
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