Answer:
The programming language is not stated; so, I'll solve this question using Java programming language
Comments are used for explanatory purpose
//Begin of Program
import java . util.*;
import java. math . RoundingMode;
import java . text . DecimalFormat;
public class keyfreq
{
private static DecimalFormat df = new DecimalFormat("0.00");
public static void main(String [] args)
{
Scanner input = new Scanner(System.in);
//Declare variable
float f0;
//Prompt user for input
System.out.print("Enter Initial Key Frequency: ");
f0 = input.nextFloat();
//Initialize number of keys
int numkey = 1;
//Print first key frequency
System.out.print("Key Frequencies: " + df.format(f0)+" ");
while(numkey<=4)
{
//Calculate next frequency
f0*= Math.pow(2,(1.0/12.0));
//Print Frequency
System.out.print(df.format(f0)+" ");
//Iterate to next frequency
numkey++;
}
}
}
//End of Program
Explanation:
See Comments in the above program
See Attachment for source file