docs: public static BigDecimal atan(BigDecimal x, MathContext mathContext) {
  		checkMathContext(mathContext);
  		MathContext mc = new MathContext(mathContext.getPrecision() + 6, mathContext.getRoundingMode());
  
  		x = x.divide(sqrt(ONE.add(x.multiply(x, mc), mc), mc), mc);
  
  		BigDecimal result = asin(x, mc);
  		return round(result, mathContext);
  	}