docs: public static BigDecimal cos(BigDecimal x, MathContext mathContext) {
  		checkMathContext(mathContext);
  		MathContext mc = new MathContext(mathContext.getPrecision() + 6, mathContext.getRoundingMode());
  
  		if (x.abs().compareTo(ROUGHLY_TWO_PI) > 0) {
  			MathContext mc2 = new MathContext(mc.getPrecision() + 4, mathContext.getRoundingMode());
  			BigDecimal twoPi = TWO.multiply(pi(mc2), mc2);
  			x = x.remainder(twoPi, mc2);
  		}
  		
  		BigDecimal result = CosCalculator.INSTANCE.calculate(x, mc);
  		return round(result, mathContext);
  	}