13 lines
245 B
JavaScript
13 lines
245 B
JavaScript
'use strict';
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var log = Math.log, sqrt = Math.sqrt;
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module.exports = function (x) {
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if (isNaN(x)) return NaN;
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x = Number(x);
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if (x < 1) return NaN;
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if (x === 1) return 0;
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if (x === Infinity) return x;
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return log(x + sqrt(x * x - 1));
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};
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