public class FloatDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		double r1 = 0, r2 = 2;
		System.out.println(parallelResist(r1,r2));
		double zz = 0.0/0;
		System.out.println(zz);
		float f = (float)Math.PI;
		System.out.println(f);
		System.out.println(Math.PI);
		float g = 123456789;
		System.out.println(g);
		System.out.println(1-0.9);

	}
	public static double parallelResist(double r1, double r2){
		double r1inv = 1/r1;
		double r2inv = 1/r2;
		return 1/(r1inv + r2inv);
	}

}