Sum of Arithmetic and Geometric Sequence

Sum of Arithmetic Sequence

The java program generates arithmetic sequence of  K numbers with common difference d.

The user has to give some input integer value to generate the sequence of numbers while running the program. These inputs are stored into variables a ,d and K.

a  - represents sequence first item

d  - sequence items common difference and

K - number of items in the sequence.

         

Arithmetic sequence =

sum of sequence 

import java.util.Scanner;

public class Sumarsequence {

 public static void main(String[] args) 
    {
    
 System.out.println("Sum of Arithmetic Sequence \n");  
 Scanner sc = new Scanner(System.in);
  
 System.out.println( "first value in sequence");
 int a = sc.nextInt();
  
 System.out.println( "common deference of sequence");
 int d = sc.nextInt();
  
 System.out.println( "K number of items in the sequence");
 int K = sc.nextInt();
 sc.close();  
  
 System.out.println(" Sequence ");  
  int sm=0; int n=0; 
  while ( n < K )   
  {      
   int s =  n*d + a;
   sm = sm+ s;
   System.out.print( s + ", ");
   n++;
  }

  System.out.println("\nSum of Sequence :" + sm);

 }

}

Output

Sum of Arithmetic Sequence 

first value in sequence
2
common deference
2
K number of items in the sequence
10

2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 

Sum of Sequence :110

Sum of Geometric Sequence

The java program generates geometric sequence of  K numbers having common ratio r.

The user has to give some input integer value to generate the sequence of numbers while running the program. These inputs are stored into variables a ,cr and K.

a  - represents sequence first item

cr  -  item's common ratio and

K - number of items in the sequence.

Geometric sequence =

sum of sequence 

import java.util.Scanner;
public class SumgeoSequence {

 public static void main(String[] args) 
 {
      
   System.out.println("Sum of Geometric Sequence n");  
   Scanner sc = new Scanner(System.in);
  
   System.out.println("Enter first item(integer) in sequence");
   int a = sc.nextInt();
  
   System.out.println( "Enter common ratio of the sequence");
   int cr = sc.nextInt();
  
   System.out.println("K items in the sequence");
   int K = sc.nextInt();
   sc.close();
     
   System.out.println("\n Sequence ");
   int n=0; int sm=0;
     
  while( n<K ) 
  {
   int s = a* (int)Math.pow(cr, n) ;
   sm =sm + s;
   System.out.print(s+", ");  
   n++;
  }
  
 System.out.println("\n Sum of Geometric Sequence :" + sm);

 }

}

Output

Sum of Geometric Sequence 

Enter first item(integer) in sequence
2
Enter common ratio 
2
K items in the sequence
10

Sequence 
2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 
 Sum of Geometric Sequence :2046