import org.mariuszgromada.math.mxparser.*; public class ParabolaFocusCalculator { public static void main(String[] args) { double a = 1.0; double b = 2.0; double c = 1.0; String expression = "(-b)/(2*a)"; Expression expr = new Expression(expression); expr.setExpressionString(expr.getExpressionString() .replaceAll("a", String.valueOf(a)) .replaceAll("b", String.valueOf(b))); double xFocus = expr.calculate(); double yFocus = a * Math.pow(xFocus, 2) + b * xFocus + c; } }