Question

Find the sum o n terms of the ap whose kth term is 5k+1

Answer 1

by substituting k=1 u will get First turn which is 6. then substituting k=2 u will get 11. subtracting both will give u common difference which is 5. then using Sn= n/2[(2a+(n-1)d)]
=n/2[7-5n]
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