Question

In an ap,if sn=1/2n(7n-1),find a2

Answer 1

ye jo sbse upr vala formula h na vo islie h

kyuki kisi b AP ki phli term ka sum hota h khud vhi term

or 2 terms ka sum hota 1st term + 2nd term

so agr hume 2nd term nikalni ho to 3 terms k sum me se agr 2 term ka sum minus krenge to 2nd term aa jayegi

hope it help u

and understand my language and my soluiton.....