Question

Show that a1,a2,........an.an+1......form anA.P where an=9-5n

Answer 1

an= 9-5n

a1= 9- 5×1 =4

a2 = 9- 5×2 = -1

a3 = 9- 5×3 = -6

Thus it forms an AP where a = 4 and d = -5 when given an =9- 5n

Hope it helped.......