docs: public static BigDecimal cot(BigDecimal x, MathContext mathContext) {
  		checkMathContext(mathContext);
  		if (x.signum() == 0) {
  			throw new ArithmeticException("Illegal cot(x) for x = 0");
  		}
  
  		MathContext mc = new MathContext(mathContext.getPrecision() + 4, mathContext.getRoundingMode());
  		BigDecimal result = cos(x, mc).divide(sin(x, mc), mc);
  		return round(result, mathContext);
  	}