NCERT Class 11 Mathematics Solutions - Chapter 9 Sequences and Series - Exercise 9.4

The NCERT Class 11 Mathematics Solutions for Chapter 9 Sequences and Series - Exercise 9.4 provides a detailed understanding of the concept of arithmetic progression and geometric progression.

Arithmetic Progression

In this exercise, the concept of arithmetic progression is explained with examples. The formula for finding the nth term of an arithmetic progression is also given. The sum of the first n terms of an arithmetic progression is also discussed along with the formula for finding it.

Code Sample for Arithmetic Progression

# To find the nth term of an AP
a = int(input("Enter the first term of AP: "))
d = int(input("Enter the common difference of AP: "))
n = int(input("Enter the value of n: "))

nth_term = a + (n-1)*d
print("The nth term of the AP is:", nth_term)

# To find the sum of first n terms of an AP
a = int(input("Enter the first term of AP: "))
d = int(input("Enter the common difference of AP: "))
n = int(input("Enter the value of n: "))

sum = (n/2)*(2*a + (n-1)*d)
print("The sum of first", n, "terms of the AP is:", sum)

Geometric Progression

In this exercise, the concept of geometric progression is explained with examples. The formula for finding the nth term of a geometric progression is also given. The sum of the first n terms of a geometric progression is also discussed along with the formula for finding it.

Code Sample for Geometric Progression

# To find the nth term of a GP
a = int(input("Enter the first term of GP: "))
r = int(input("Enter the common ratio of GP: "))
n = int(input("Enter the value of n: "))

nth_term = a*r**(n-1)
print("The nth term of the GP is:", nth_term)

# To find the sum of first n terms of a GP
a = int(input("Enter the first term of GP: "))
r = int(input("Enter the common ratio of GP: "))
n = int(input("Enter the value of n: "))

if r == 1:
    sum = n*a
else:
    sum = (a*(1 - r**n))/(1 - r)
print("The sum of first", n, "terms of the GP is:", sum)

By understanding the concepts and solving the problems in this exercise, students will be able to master the concept of sequences and series.