Question

termos gerais de P.A e P.G ?

Answer 1

P.A :

Achar a razão : $\mathtt{R = A_2 - A_1}$

Termo geral : $\mathtt{A_n = A_1 + (n-1)~.~R}$

Soma de termo P.A : $\mathtt{S_n = \dfrac{(A_1 + A_n)~.~n}{2}}$

P.G :

Achar a razão : $\mathtt{q = A_2 \div A_1}$

Termo geral : $\mathtt{A_n = A_1 ~.~q^{n-1}}$

Soma de termos P.G : $\mathtt{S_n = \dfrac{A_1~.~(q^n -1)}{q-1}}$

Answer 2

PA

an = a1 + ( n - 1)r

PG

an = a1 . qⁿ⁻¹