Question

the sum of first n term of the Apis 4n2+2n find nth term ,3rd term ,15th ter. and sum of first three term​

Answer 1

Answer:

Sn=n2{2a+(n−1)d}

4n2+2n=n2{2a+(n−1)d}

4n2+2n=an+n2(n−1)d

4n2+2n=an+n2d2−nd2

4n2+2n=n{a−d2}+d2n2

a−d2=2,a−82=2

d2=4,d=8

an+a+(n−1)d

=6+(n−1)8

`8n-2.

Step-by-step explanation: