Question

Calcule o 8° termo da p.g (-72,-24,-8...)

Answer 1

P.G.(-42 ; -24 ; -8 ; .........)
q = a 2 / a 1
q = -24/-72
q = 1/3
A 8 = A 1 .q^n - 1
A 8 = -72 . q^8-1
A 8 = -72 . q^7
a 8 = -72.(1/3)^7
a 8 = -72 . (1/2187)
a 8 = -72/2187
a 8 = - 8 / 243