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Function std.math.trigonometry.acosh

Calculates the inverse hyperbolic cosine of x.

real acosh (
  real x
) pure nothrow @nogc @safe;

double acosh (
  double x
) pure nothrow @nogc @safe;

float acosh (
  float x
) pure nothrow @nogc @safe;

Mathematically, acosh(x) = log(x + sqrt( x*x - 1))

Domain X Range Y
1..∞ 0..∞

Special Values
x acosh(x)
NAN NAN
<1 NAN
1 0
+∞ +∞

Example

import std.math.traits : isIdentical, isNaN;

assert(isNaN(acosh(0.9)));
assert(isNaN(acosh(real.nan)));
assert(isIdentical(acosh(1.0), 0.0));
writeln(acosh(real.infinity)); // real.infinity
assert(isNaN(acosh(0.5)));

Authors

Walter Bright, Don Clugston, Conversion of CEPHES math library to D by Iain Buclaw and David Nadlinger

License

Boost License 1.0.