Java examples for java.lang:Math Trigonometric Function
Calculate arc sin
/*// w w w .j a v a2 s.co m * Copyright 2009 Andrey Khalzov, and individual contributors as indicated by the @author tag. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and limitations under the License. */ //package com.java2s; public class Main { public static final double PI_2 = Math.PI / 2; public static final double PI_6 = Math.PI / 6; public static final double SQRT_3 = Math.sqrt(3); public static double arcsin(double x) { /* check for exceptions */ if (x <= -1) { return -PI_2; } if (x >= 1) { return PI_2; } /* transform the argument */ x /= Math.sqrt(1 - x * x); return arctan(x); } public static double arctan(double x) { int sta = 0; int sp = 0; double x2; double a; /* check up the sign change */ if (x < 0) { x = -x; sta |= 1; } /* check up the invertation */ if (x > 1) { x = 1 / x; sta |= 2; } /* process shrinking the domain until x<PI/12 */ while (x > PI_2) { sp++; a = x + SQRT_3; a = 1 / a; x *= SQRT_3; x -= 1; x *= a; } /* calculation core */ x2 = x * x; a = x2 + 1.4087812; a = 0.55913709 / a; a += 0.60310579; a -= 0.05160454 * x2; a *= x; /* process until sp=0 */ while (sp > 0) { a += PI_6; sp--; } /* invertation took place */ if ((sta & 2) > 0) { a = PI_2 - a; } /* sign change took place */ if ((sta & 1) > 0) { a = -a; } return a; } }