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Math functions for BigDecimal.

There is a newer version: 2.3.2

package ch.obermuhlner.math.big.internal;

import java.math.BigDecimal;
import java.math.MathContext;

import ch.obermuhlner.math.big.BigRational;

/**
 * Calculates arc sinus using the Maclaurin series.
 * 
 * See Wikipedia: Taylorreihe
 * 
 * No argument checking or optimizations are done.
 * This implementation is not intended to be called directly.
 */
public class AsinCalculator extends SeriesCalculator {

	public static final AsinCalculator INSTANCE = new AsinCalculator();
	
	private int n = 0;
	private BigRational factorial2n = BigRational.ONE;
	private BigRational factorialN = BigRational.ONE;
	private BigRational fourPowerN = BigRational.ONE;
	
	private AsinCalculator() {
	}
	
	@Override
	protected BigRational getCurrentFactor() {
		BigRational factor = factorial2n.divide(fourPowerN.multiply(factorialN).multiply(factorialN).multiply(2 * n + 1));
		return factor;
	}
	
	@Override
	protected void calculateNextFactor() {
		n++;
		factorial2n = factorial2n.multiply(2 * n - 1).multiply(2 * n);
		factorialN = factorialN.multiply(n);
		fourPowerN = fourPowerN.multiply(4);
	}
	
	@Override
	protected PowerIterator createPowerIterator(BigDecimal x, MathContext mathContext) {
		return new PowerTwoNPlusOneIterator(x, mathContext);
	}
}