T = (½) - ³ + ( - ² / 5) - ² + (⁴ / 7) - ¹?

Saludos

(a / b) ^ - n = (b / a) ^ n (a / b) ^ n = (a ^ n) / (b ^ n)

(1 / 2) ^ - 3 = (2 / 1) ^ 3 = 2 ^ 3 = 8

( - 2 / 5) ^ - 2 = ( - 5 / 2) ^ 2 = ( - 5) ^ 2 / (2) ^ 2 = 25 / 4

(4 / 7) ^ - 1 = 7 / 4

(1 / 2) ^ - 3 + ( - 2 / 5) ^ - 2 + (4 / 7) ^ - 1 =

8 + 25 / 4 + 7 / 4 = 8 + 32 / 4 = 8 + 16 / 2 = 8 + 8 = 16

R / 16.