1,1/3,1/9,1/27,1/18,( )
1+9+18+27=?
1/3+1/9+/1/27+...+1/3^7=?
1/3,-1/9,1/27,-1/81...求数列
12,9,21,27,15,60,3,1,18
1-1/3-1/9-1/27-1/81-1/243-1/729-1/2187
求1+1/3+1/9+1/27+1/81+...+1/243+1/729
计算:1+1/3+1/9+1/27+1/81+1/243+1/729
1-1/3-1/9-1/27-1/81-1/243-1/729=?
计算:3/1+9/1+27/1+81/1+243/1+729/1+2187/1
计算:1-1/3-1/9-1/27-1/81-1/243-1/729
1/3-1/9+1/27+...+(-1)^n-1*1/3^n的极限
3/1+9/1+27/1+81/1+243/1+729/1怎么算?