Calculate Frequency Using java

import java.util.*;

public class Ch1Q38
{
 public static void main(String[] args)
  {Scanner kbd = new Scanner(System.in);
  System.out.print("Enter inductance, capacitance and resistance: ");
  double l = kbd.nextDouble();
  double c = kbd.nextDouble();
  double r = kbd.nextDouble();
  double f = Math.sqrt(1/l/c - r*r/4/c/c);
  System.out.println("Freq = " + f);
    }
}