Question

1 supra 3 plus 1 supra 3 la puterea a doua plus 1 supra 3 la puterea a treia plus 1 supra 3 la puterea a patra plus 1 supra 3 la puterea a 5-a plus 1 supra 3 la puterea a șasea egal

Answer 1

A=1/3 +1/3²+1/3³+1/3^4+1/3^5+1/3^6 |x3
3A=1+1/3 +1/3²+1/3³+1/3^4+1/3^5
3A-A=2A=(1+1/3 +1/3²+1/3³+1/3^4+1/3^5)-(1/3 +1/3²+1/3³+1/3^4+1/3^5+1/3^6)
                =1-1/3^6
2A=(3^6-1)/3^6
A=(3^6-1)/2.3^6
A=(729-1)/729.2=728/1458=364/729