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calc/help/acosh
Landon Curt Noll 1c839dfede add logn and error checking for invalue eps and epsilon values
Add new logn(x, n [,eps]) builtin to compute logarithms to base n.

Verify that eps arguments (error tolerance arguments that override
the default epsilon value) to builtin functions have proper values.
Previously the eps argument had little to no value checks for
many builtin functions.

Document in help files for builtin functions that take eps arguments,
the LIMIT range for such eps values.
2023-08-31 22:33:41 -07:00

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NAME
acosh - inverse hyperbolic cosine
SYNOPSIS
acosh(x [,eps])
TYPES
x real, x >= 1
eps 0 < real < 1, defaults to epsilon()
return nonnegative real
DESCRIPTION
Returns the acosh of x to a multiple of eps with error less in
absolute value than .75 * eps.
acosh(x) is the nonnegative real number v for which cosh(v) = x.
It is given by
acosh(x) = ln(x + sqrt(x^2 - 1))
EXAMPLE
; print acosh(2, 1e-5), acosh(2, 1e-10), acosh(2, 1e-15), acosh(2, 1e-20)
1.31696 1.3169578969 1.316957896924817 1.31695789692481670862
LIMITS
0 < eps < 1
LINK LIBRARY
NUMBER *qacosh(NUMBER *x, NUMBER *eps)
SEE ALSO
asinh, atanh, asech, acsch, acoth, epsilon
## Copyright (C) 1999,2023 Landon Curt Noll
##
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## Under source code control: 1994/03/19 01:40:24
## File existed as early as: 1994
##
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