Compute Inverse Hyperbolic Cosine

Examples in JavaScript
console.log(Math.acosh(0.999999999999));
// expected output: NaN

console.log(Math.acosh(2.5));
// expected output: 1.566799236972411

Math.acosh(-1);  // NaN
Math.acosh(0);   // NaN
Math.acosh(0.5); // NaN
Math.acosh(1);   // 0
Math.acosh(2);   // 1.3169578969248166