Find the sum of odd integers from 1 to 2 | Class 11 Mathematics Chapter Sequence and Series, Sequence and Series NCERT Solutions

Question: Find the sum of odd integers from 1 to 2001.
Answer:

The odd integers from 1 to 2001 are 1, 3, 5, …1999, 2001.
 
This sequence forms an A.P.
 
Here, first term, a = 1
 
Common difference, d = 2
 
Here,
 
\begin{align} a + (n - 1)d = 2001 \end{align}
 
\begin{align} => 1 + (n - 1)(2) = 2001 \end{align}
 
\begin{align} => 2n -2 = 2000 \end{align}
 
\begin{align} => n = 1001 \end{align}
 
\begin{align} S_n = \frac {n}{2}\left[2a + (n -1)d\right]\end{align}
 
\begin{align} \therefore S_n = \frac {1001}{2}\left[2 × 1 + (1001 -1)×2\right]\end{align}
 
\begin{align} = \frac {1001}{2}\left[2 + 1000×2\right]\end{align}
 
\begin{align} = \frac {1001}{2} × 2002\end{align}
 
\begin{align} =1001 × 1001 \end{align}
 
\begin{align} = 1002001 \end{align}
 
Thus, the sum of odd numbers from 1 to 2001 is 1002001.
 


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Sequence and Series.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

  • Ravi Kiran
  • 2017-02-24 21:06:58

WRONG AF!


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 11 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 1: Find the sum of odd integers from 1 to 2001.....