Question

Find the terms of an a.p given the sn= 3n +16n.n find the common diffrence of an a.p

Answer 1

Step-by-step explanation:

Solution :-

Given S

n

=3n

2

+5n

S

1

=a

1

=3(1)

2

+5(1)=3+5=8

S

2

=a

1

+a

2

=3(2)

2

+5(2)=3(4)+10=22

⇒8+a

2

=22

⇒a

2

=14

S

3

=a

1

+a

2

+a

3

=3(3)

2

+5(3)=27+15=42

⇒a

3

=S

3

−S

2

=42−22=20

d=a

2

−a

1

=a

3

−a

2

=14−8=20−14=6

The terms of an A.P are 8,14,20……

with common difference 6