Question

The fifth term of an ap of n terms whose sum is n^2-2n

Answer 1

Answer:

7

Step-by-step explanation:

S1 = (1)^2 - 2*1 = 1-2 = -1

S2 = (2)^2 -2*2 = 0

S3 = (3)^2 -2*3 = 9-6 = 3

S4 = (4)^2 - 2*4 = 16-8 = 8

S1 = A1 = -1

A2 = S2 - S1 = 0-(-1) = 1

A3 = S3 - S2 = 3 -0 = 3

A4 = S4 - S3 = 8-3 = 5

here

A1 = -1

d = 2

a5 = -1 + (5-1) *2

A5 = -1 + 8 = 7

Answer 2

Answer:

first term is 1"2-2*1=-1

s2=a1+a2=4-4=0

a2=1

s.d.=2

a5=-1+4*2=7

hope it helps you