Question

if the first term of an Arithmetic sequence is (n) and common difference is 2n . then prove that the sum of first n terms is
$n 3$



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Answer 1

Step-by-step explanation:

a=n , c.d = 2n , term = n

sn = n/2{2n+(n-1)2n}

=n/2(2n+2nsquare- 2n)

=n/2•2nsquare

answer is n cube