Question

sn=3nsquare-2n find the ap.

Answer 1

hey
given
Sn=3n²-2n
if you put 1 in place of n the sum of first term come it means that it is only first term
so let's calculate
s×1=3×1²-2×1
s=3-2
s=1 it means that first term is 1 because first sum is equal to first term
a=1
now
to find d
Sn=3n²-2n
put 2 now in place of n to get sum of first term that is 1 and other that we have to find.
S×2=3×2²-2×2
S×2=3×4-2×2
S×2=12-4
S×2=8
s=4
now sum of two terms is 4
it mean
4=first term+second term
putting first term that we calculate
4=1+second term
second term=4-1
second term=3
hence
difference=second term-first term
d=3-1
d=2
hence we know d and a
a=1,d=2
hence AP is

a,a+d,a+2d,a+3d
that is
1,3,5,7........,..,