Respuesta :

sum = A/(1-R) = 1/[1-(-1/3)] = 1/(4/3)

= 3/4 = 0.75

this is an infinite series

its summation = initial value / (1-common ratio)

initial value when n=1 is (-1/3)^(1-1) = 1

common ratio is -1/3

summation = 1/(1-(-1/3))

= 1/(1+1/3)

=3/4

=0.75