Objective question in Mathematics Jr

IIT JEE 2015 Help › Class VII-X Mathematics questions › Objective question in Mathematics Jr

Find the sum of the series

1/(1*3)+1/(2*4)+1/(3*5)+1/(4*6)+.......+1/(8*10)=

#Mathematics #Class VII-X Mathematics

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2 Answers

21

Anurag Choudhury ·2012-08-31 02:34:18

Re-arranging the series :-
1/(1.3)+1/(3.5)+1/(5.7)+1/(7.9) + 1/(2.4)+1/(4.6)+1/(6.8)+1/(8.10)
=1/3(1+1/5)+1/7(1/5+1/9) + 1/8(1+1/3)+1/16(1/3+1/5)
=2/5+2/45 + 1/6+1/30
=29/45
How is the answer 7/10?
Could anyone explain this please?

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Anurag Choudhury Checked the sum on the calculator...answer is 29/45.
Upvote·0· Reply ·2012-09-04 19:37:08
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2305

Shaswata Roy ·2013-01-29 05:58:44

Write the general term 1n(n+2) as 12[1n - 1n+2]
and you will get your desired result

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