Question

3^1+3^2+3^3+...+3^10=?

Answer 1

$b_{1}=3 \\ q = 3 \\ b_{n}= 3^{10} \\ n=10$

=> $\\ S_{n}= b_{1} * \frac{q^{n}-1 }{q-1} =3* \frac{ 3^{10}-1}{10-1} =3* \frac{3^{10}-1 }{9}=6560$

=> Suma este egala cu 6560.