Find the sum to n terms of the | Class 11 Mathematics Chapter Sequence and Series, Sequence and Series NCERT Solutions

Question:

Find the sum to n terms of the sequence, 8, 88, 888, 8888…

Answer:

The given sequence is 8, 88, 888, 8888…

This sequence is not a G.P. However, it can be changed to G.P. by writing the terms as

S_n = 8 + 88 + 888 + 8888 + …………….. to n terms

$equals 8 over 9 open square brackets 9 plus 99 plus 999 plus 9999 plus.......... t o space n space t e r m s close square brackets equals 8 over 9 open square brackets open parentheses 10 minus 1 close parentheses plus open parentheses 10 squared minus 1 close parentheses plus open parentheses 10 cubed minus 1 close parentheses plus open parentheses 10 to the power of 4 minus 1 close parentheses plus........ t o to the power of space n space t e r m s close square brackets equals 8 over 9 open square brackets open parentheses 10 plus 10 squared space plus space....... n space t e r m s close parentheses space minus space open parentheses 1 plus 1 plus 1 plus... n space t e r m s close parentheses close square brackets equals 8 over 9 open square brackets fraction numerator 10 open parentheses 10 to the power of n minus 1 close parentheses over denominator 10 minus 1 end fraction space minus space n close square brackets equals 8 over 9 open square brackets fraction numerator 10 open parentheses 10 to the power of n minus 1 close parentheses over denominator 9 end fraction space minus space n close square brackets equals 80 over 81 open parentheses 10 to the power of n minus 1 close parentheses space minus space 8 over 9 n$

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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

ayush
2019-03-07 15:42:36

thanks lord

ayush
2019-03-07 15:42:19

thanks lord

ABHISHEK ANAND
2018-03-31 17:26:57

what will be the answer if sum of infinity term are asked.

Sup
2017-02-15 07:35:27

TQ very very much

Amrith
2016-10-04 20:52:22

Thank you very muchðð

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Welcome to the NCERT Solutions for Class 11 Mathematics - Chapter . This page offers a step-by-step solution to the specific question from Excercise 3 , Question 18: Find the sum to n terms of the sequence, 8, 88, 888, 8888…....

Find the sum to n terms of the | Class 11 Mathematics Chapter Sequence and Series, Sequence and Series NCERT Solutions

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