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प्रश्न
Find the sum of the following arithmetic progressions:
1, 3, 5, 7, ... to 12 terms
उत्तर
1, 3, 5, 7, ... to 12 terms
Common difference of the A.P. (d)
`= a_2 - a_1`
= 3 - 1
= 2
Number of terms (n) = 12
First term for the given A.P (a) = 1
So using the formula we get
`S_n = 12/2 [2(1) = (12 - 1)(2)]`
= (6)[2 + (11)(2)]
= (6)[24]
= 144
Therefore, the sum of first 12 terms for the given A.P. is 144
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संबंधित प्रश्न
Find the sum of all odd natural numbers less than 50.
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The sum of the first n terms of an AP is given by `s_n = ( 3n^2 - n) ` Find its
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(ii) first term and
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Q.13
Find the sum of all members from 50 to 250 which divisible by 6 and find t13.
Find the value of x, when in the A.P. given below 2 + 6 + 10 + ... + x = 1800.
Find the sum of first 1000 positive integers.
Activity :- Let 1 + 2 + 3 + ........ + 1000
Using formula for the sum of first n terms of an A.P.,
Sn = `square`
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= 500 × 1001
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