Question

if an a.p if d= -3 n= 8 and its nth term=5 then is a​

Answer 1

Step-by-step explanation:

Given,

S

p

=p(p+1)(p+2)

⇒S

p

=p

3

+3p

2

+2p

and

S

p−1

=(p−1)(p)(p+1)

⇒S

p−1

=p

3

−p

Now, pth term,

a

p

=S

p

−S

p−1

=p

3

+3p

2

+2p−(p

3

−p)

∴a

p

=3p

2

+3p

Now,

a

10

=3(10)

2

+3(10)

=300+30

=330