Question

Sa se calculeze suma 1+1/3+1/3la2+1/3la3+1/3la4

Answer 1

$1+ \frac{1}{3} +( \frac{1}{3}) ^{2} +( \frac{1}{3} ) ^{3}+( \frac{1}{3}) ^{4} =1+ \frac{1}{3} + \frac{1}{9} + \frac{1}{27} + \frac{1}{81} = \frac{81+27+9+3+1}{81} = \frac{121}{81}$