Geometric Progression in Python

Hey Folks! In this tutorial, we will understand what a Geometric Progression is and how to implement the same in the Python programming language.

Introduction to Geometric Progression (G.P.)

Geometric Series is a succession of elements in which the next item is acquired by multiplying the previous item by the common ratio.

A G.P. Series is a number series in which the common ratio of any successive integers (items) is always the same.

This Sum of the G.P Series is based on a mathematical formula.

Sn = a(rⁿ) / (1- r)
Tn = ar^(n-1)

Geometric Progress in Python

Let’s get into the understanding of how geometric progression works in Python. We’ll take a look at two different examples of the same to get a better understanding.

1. Print first n terms of the Geometric Progression

There are a number of steps involved to achieve the n GP terms. The steps are as follows:

Step 1 – Take the input of a ( the first term ), r( the common ratio), and n ( the number of terms )
Step 2 – Take a loop from 1 to n+1 and compute the nth term in every iteration and keep printing the terms.

# 1. Take input of 'a','r' and 'n'
a = int(input("Enter the value of a: "))
r = int(input("Enter the value of r: "))
n = int(input("Enter the value of n: "))

# 2. Loop for n terms
for i in range(1,n+1):
    t_n = a * r**(i-1)
    print(t_n)

Enter the value of a: 1
Enter the value of r: 2
Enter the value of n: 10
1
2
4
8
16
32
64
128
256
512

2. Get Sum of first n terms in Geometric Progression

There are a number of steps involved to achieve the sum of first n GP terms. The steps are as follows:

Step 1 – Take the input of a (the first term), r(the common ratio), and n (the number of terms)
Step 2 – Use the formula mentioned above to compute the sum of the first ‘n’ terms.

# 1. Take input of 'a','r' and 'n'
a = int(input("Enter the value of a: "))
r = int(input("Enter the value of r: "))
n = int(input("Enter the value of n: "))

if(r>1):
  S_n = (a*(r**n))/(r-1)
else:
  S_n = (a*(r**n))/(1-r)

print("Sum of n terms: ",S_n)

Enter the value of a: 1
Enter the value of r: 2
Enter the value of n: 5
Sum of n terms:  32.0

Conclusion

Congratulations! You just learned how to implement Geometric Progression in Python. Hope you enjoyed it! 😇

Liked the tutorial? In any case, I would recommend you to have a look at the tutorials mentioned below:

Thank you for taking your time out! Hope you learned something new!! 😄