Question

the sum of first n term of an ap is 3 and square + 2 and find its and term and the series​

Answer 1

Sn=3n^2+2n

TO FIND:nth term

we have to find value of a&d i.e

first term &common difference

put n=1

S1=3(1)^2+2(1)

s1=3+2

s1=5

putn=2

s2=3(2)^2+2(2)

s2=12+4

s2=16

now,

a=t1=s1

a=t1=5

t2=s2-s1

=16-5

t2=11

a=5

d=t2-t1

=11-5

d=6

tn=a+(n-1)d...................(formula)

tn=5+(n-1)6....(substituting value)

tn=5+6n-6

tn=6n-1

As a result

the nth term is 6n-1