29 lines
565 B
JavaScript
29 lines
565 B
JavaScript
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var utils = require('../utils')
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, nodes = require('../nodes');
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/**
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* Return the tangent of the given `angle`.
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*
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* @param {Unit} angle
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* @return {Unit}
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* @api public
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*/
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module.exports = function tan(angle) {
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utils.assertType(angle, 'unit', 'angle');
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var radians = angle.val;
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if (angle.type === 'deg') {
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radians *= Math.PI / 180;
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}
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var m = Math.pow(10, 9);
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var sin = Math.round(Math.sin(radians) * m) / m
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, cos = Math.round(Math.cos(radians) * m) / m
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, tan = Math.round(m * sin / cos ) / m;
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return new nodes.Unit(tan, '');
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};
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