Question

Determine a soma do termos da P.G
(-8, -16, -32, -64, -128, -256, -512)

Answer 1

$Sn = \frac{a1*(q^n-1)}{q-1} \\ \\ S5= \frac{-8*(2^5-1)}{2-1} \\ \\ S5 = -8 *(32-1) \\ \\ S5 = -8 *31 \\ \\ S5 = -248$