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Find the sum of first odd 10 natural numbers?\xa0 |
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Answer» The 1st 10 odd natural numbers are 1,3,5,7.....Here, a = 1, d = 2We know, Sn\xa0= n/2 {2a + (n-1)d}S10\xa0= 10/2 {2×1 + (10-1)×2} = 5 (2 + 9×2) = 5 (2 + 18) = 5\xa0×\xa020 = 100 (Answer) Sum of First N Natural Odd Numbers = N2Sum of First N Natural Even Numbers = N2\xa0+ Nwhere n is number of terms.\xa0for example : sum of first 5 even numbers = (5)2\xa0+ 5 = 30\xa0sum of first 5 ODD\xa0numbers = ( 5)2 = 25\xa0 Here the AP is 1, 3, 5, ......, 19a = 1, d = 1, n = 10, l = 19Sn = (n/2)(a + l)S10\xa0= (10/2)(1 + 19) = 5 × 20 = 100 You can get your doubt cleared with teachers from IIT and AIIMS on HashLearn. Download the HashLearn app here http://bit.ly/2fDYZtb |
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