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If nth term of an AP is 2n+1.then what is the sum of its first three terms? |
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Answer» An = 2n + 1Let n be 1a1 = 2(1) + 1a1 = 3Let n be 2a2 = 2(2) + 1= 4 + 1= 5Let n be 3a3 = 2(3) + 1a3 = 7a1 + a2 + a3 = 3 + 5 + 7 = 15\xa0 First put n=1and then put n=2 u will get the 1st term and the 2nd term and then find d 15 |
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