Question

Encontre o termo geral da P.G (2,1,...)

Answer 1

$\mathrm{PG=(a_1,a_2,\dots,a_n)=(2,1,\dots, a_n)}\\\\ \mathrm{q=\dfrac{a_2}{a_1}\ \to\ q=\dfrac{1}{2}}\\\\ \mathrm{a_n=a_1.q^{n-1}\ \to\ a_n=2.\bigg(\dfrac{1}{2}\bigg)^{n-1}}\\\\ \mathrm{a_n=2.\big(2^{-1}\big)^{n-1}\ \to\ a_n=2.2^{1-n}}\\\\ \mathrm{a_n=2^{1+1-n}\ \to\ \mathbf{a_n=2^{2-n}}}$

Answer 2

Resposta:

An=a1*q^n-1

An=^2*1/2^n-1

An=2/2^n-1

An=2^(n-1)-1

An=2^n-2