Question

In A. P Sn=8n-2 then find a4=?

Answer 1

Step-by-step explanation:

Sn = 8n - 2

S1 = 8(1) - 2

= 8 - 2 = 6 = a1

S2 = 8(2) - 2

= 16 - 2

= 14

a2 = S2 - S1

= 14 - 6

= 8

now,

d = a2 - a1

= 8 - 6

= 2

now,

a = 6

d = 2

a4 = a + 3d

= 6 + 3 ( 2 )

= 6 + 6

= 12

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