Question

 If the sum of the first n term of an AP is 4n - n* What is the fifth term of AP?​

Answer 1

Answer:

A.P is 4n-n

Let n= 1,2,3,.......

So

n=1, S1=4n-n

= 4*1-1 = 3

n=2, S2= 4*2-2 =6

Then,

a1+a2 = 6

3+a2 = 6

a2 = 6-3

a2 = 3

d = a2-a1

= 3-3 = 0

a5 = a+4d

= 3 +4*0

a5 = 3