Release calc version 2.10.2t30

help/asech

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+NAME
+    asech - inverse hyperbolic secant
+
+SYNOPSIS
+    asech(x [,eps])
+
+TYPES
+    x		real, 0 < x <= 1
+    eps		nonzero real, defaults to epsilon()
+
+    return	real
+
+DESCRIPTION
+    Returns the asech of x to a multiple of eps with error less in
+    absolute value than .75 * eps.
+
+    asech(x) = ln((1 + sqrt(1 - x^2))/x) is the real number v for which
+    sech(v) = x.
+
+EXAMPLE
+    > print asech(.5,1e-5), asech(.5,1e-10), asech(.5,1e-15), asech(.5,1e-20)
+    1.31696 1.3169578969 1.316957896924817 1.31695789692481670862
+
+LIMITS
+    unlike sin and cos, x must be real
+    0 < x <= 1
+    eps > 0
+
+LIBRARY
+    NUMBER *qasech(NUMBER *x, NUMBER *eps)
+
+SEE ALSO
+    asinh, acosh, atanh, acsch, acoth, epsilon