The suitable formula to find the sum of first n terms of the AP 1 + 3 + 5 + 7 + ------ is ______
(a) 2 n² (b) n(n + 1 ) (c) n² (d) n(n-1)
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Sn = n/2(2a+(n-1)d)
Here a=1 and d=2
Sn= n/2(2×1+(n-1)2)
Sn=n/2(2+2n-2)
Sn=n/2×2n
Sn=n2
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