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The nth term of a sequence is 3n-2n. Find the sum of first 15 term. |
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Answer» 15 an = 3n-2n =} a1 = 3(1)-2(1) =} a = 1 =} Similarly, a2 = 2 , a3 = 3 =} AP = 1,2,3,.... =} Sn = n/2[2a+(n-1)d] =} 15/2[2(1)+(15-1)1] =} 120 120 3 |
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