Question

Find the second term and n^th term of an A.P. whose 6^th term is 12 and the 8^th term is 22.

Answer 1

a₆ = a + 5d

12 = a + 5d …(i)

a₈ = a + 7d

22 = a + 7d …(ii)

Subtracting (i) from (ii), we get,

10 = 2d

d = 5

from (i)

12 = a + 5(5)

12 = a + 25

a = -13

a₂ = a +d

= -13 +5

= - 8

a_n = a + (n -1)d

= - 13 + (n - 1)5

= -18 + 5n