Question

Calculati succe.
1+3+3²+......+3 la 29

Answer 1

Foloesti folosesti formula de la progresii geometrice:

$\frac{ 3^{29}-1 }{3-1}$.

Answer 2

$1+3+3^2+......+3^2^9= \\ = \frac{3^2^9^+^1-1}{3-1}= \\ = \frac{3^3^0-1}{2}$