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| var HALF_PI = Math.PI/2;
|
| module.exports = function(eccent, phi, sinphi) {
| if (Math.abs(phi) > HALF_PI) {
| return Number.NaN;
| }
| if (phi === HALF_PI) {
| return Number.POSITIVE_INFINITY;
| }
| if (phi === -1 * HALF_PI) {
| return Number.NEGATIVE_INFINITY;
| }
|
| var con = eccent * sinphi;
| return Math.log(Math.tan((HALF_PI + phi) / 2)) + eccent * Math.log((1 - con) / (1 + con)) / 2;
| };
|
|
