Diketahui 1/16 + 1/8 + 1/4+....+16=x.nilai x adalah

a = 1/16
U2 = a r
1/8 = (1/16) r
   r = 1/8 x 16
     = 2

Un = a rⁿ⁻¹
16  = (1/16) (2)ⁿ⁻¹
16 x 16 = 2ⁿ-¹
        2⁸ = 2ⁿ⁻¹
n - 1 = 8
     n = 8 + 1
        = 9

Sn = a (rⁿ - 1) / r - 1
S9 = 1/16 (2⁹ - 1) / 2 - 1
      = 1/16 (511)
      = 31,9
S9 = x = 31,9