Question

The sum of first 4 term is an Ap is 60 and the sum of squares is 84.​

Answer 1

Step-by-step explanation:

Consider the four terms; a - 3d , a - d , a + d and a + 3d

so ,a - 3d + a - d + a + d + a + 3d = 16

=> 4a = 16 => a = 4

And (a - 3d)² + (a - d)² + (a + d)² + (a + 3d)² = 84

=> 4a² + 20d² = 84

=> 20d² = 84 - 64

=> 20d² = 20

=> 20d² = 20

=> d = ± 1

therefore: terms of A.P. = 1 , 3 , 5 , 7 or 7 , 5 , 3 , 1 -----------> (Ans)