Question

If the sum of nth terms of an AP is n2+4n then 15 th term will be

Answer 1

Answer:

15th term is 33

Step-by-step explanation:

Sn = n^2 + 4n

S1 = 1² + 4(1)

= 1 + 4

= 5

S2 = 2² + 4(2)

= 4 + 8

= 12

S1 = a1 = 5

S2 = a1 + a2 = 12

5 + a2 = 12

a2 = 12 - 5

a2 = 7

d = a2 - a1 = 7 - 5 = 2

15th term = a + 14d

= 5 + 14(2)

= 5 + 28

= 33

hope you get your answer