2/(3/4-1/6)x5/9
1x5+2x5+3x5+4x5+5x5… 麻烦给我一个公式.
sn=(2-3x5^-1)+(4-3x5^-2)+…+(2n-3x5^-n)要详解答案,急用!
必修五数列综合练习:求和:(2-3x5^-1)+(4-3x5^-2)+…+(2n-3x5^-n) 急用!
求前n项和1.1/(2X5),1/(5X8),1/(8X11)...2.2^2/(1X3),4^2/(3X5),6^2/
(9/5X10/7-3/1)X5/6
(1+2+3+4+5+6+7+8+9+10+11+12+13+14+15)x5=?
1/1x2+1/2x3+1/3x4+1/4x5.1/9x10简算
11/4/(2/3-(1/2+3/5)x5/9)怎么算
[(2/3-1/4)÷5/6+4/5]X5/11
1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101
(2分之1-6分之1)x5分之3除5分之1= 6分之5+3分之5x5分之4= (6分之1+4分之3
求和(1)(a-1)+(a²-2)+…+(an-n)(2)(2-3X5^-1)+(4-3X5^-2)+…+(2