Question

na sucessao (4, 2, 1, 1/2, 1/4, 1/8, ...) caucule (a4 +a6)-a2

Answer 1

-a2*a4 = -a^2 8
-a2*a6 = -a^2 12

-a^2 8+(-a^2 12) = -2a^2a 20

Answer 2

A4=1/2, a6=1/8, a2=2 -> (1/2+1/8)-2= (4/8-1/8)-2= 3/8-2= 3/8-16/8= -13/8