Question

Dades os termos e razão a determine os Cinco primuros termes de cada PG. a) a1= -80 ; q= -1/4?​

Answer 1

Explicação passo a passo:

$Termo~~geral\\ \\ a_n=a_1.q^{n-1}$

---------------------------------------

$a_1=-80\\ \\ a_2=a_1.q=-80.(-{1\over4})=+{80\over4}=20\\ \\ a_3=a_1.q^2=-80.(-{1\over4})^2=-80.(+{1\over16})=-{80\over16}=-5\\ \\ a_4=a_1.q^3=-80.(-{1\over4})^3=-80.(-{1\over64})=+{80\over64}={5\over4}\\ \\ a_5=a_1.q^4=-80.(-{1\over4})^4=-80.(+{1\over256})=-{80\over256}=-{5\over16}$

$P.G(-80,+20,-5,+{5\over4},-{5\over16})$