module.exports = function (math) { var util = require('../../util/index'), Complex = require('../../type/Complex'), collection = require('../../type/collection'), isNumBool = util.number.isNumBool, isComplex = Complex.isComplex, isCollection = collection.isCollection; /** * Calculate the inverse sine of a value * * asin(x) * * For matrices, the function is evaluated element wise. * * @param {Number | Boolean | Complex | Array | Matrix} x * @return {Number | Complex | Array | Matrix} res * * @see http://mathworld.wolfram.com/InverseSine.html */ math.asin = function asin(x) { if (arguments.length != 1) { throw new util.error.ArgumentsError('asin', arguments.length, 1); } if (isNumBool(x)) { if (x >= -1 && x <= 1) { return Math.asin(x); } else { return asin(new Complex(x, 0)); } } if (isComplex(x)) { // asin(z) = -i*log(iz + sqrt(1-z^2)) var re = x.re; var im = x.im; var temp1 = new Complex( im * im - re * re + 1.0, -2.0 * re * im ); var temp2 = math.sqrt(temp1); var temp3; if (temp2 instanceof Complex) { temp3 = new Complex( temp2.re - im, temp2.im + re ); } else { temp3 = new Complex( temp2 - im, re ); } var temp4 = math.log(temp3); if (temp4 instanceof Complex) { return new Complex(temp4.im, -temp4.re); } else { return new Complex(0, -temp4); } } if (isCollection(x)) { return collection.deepMap(x, asin); } if (x.valueOf() !== x) { // fallback on the objects primitive value return asin(x.valueOf()); } throw new util.error.UnsupportedTypeError('asin', x); }; };