1/1x2= 1-1/2
1/2x3=1/2-1/3
依此类推
原式 = 1-1/2+1/2-1/3+1/3-...+1/19-1/20
=1-1/20
=19/20
1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+.+1/18x19+1/19x20 计算方法与结果
1个回答
相关问题
-
1/2x3十1/3x4十1/4x5十……十1/18x19十1/19x20=?
-
1x2/1+2x3/1+3x4/1+4x5/1.19x20/1
-
观察下列单项式：1/2x,-2/3x^2,3/4x^3,-4/5x^4,5/6x^5,…,19/20x^19,-20/2
-
解方程：（1）2x-19=7x+31 (2)20-2x=x-1 (3)19-x=100-10x (4)1/3x+5=2/
-
1x2x3x4x5x6x……x19x20
-
-①4.1x+221.4=4.25x+216 ②43-2(5+3)=3+6(x-1) ③27=x2[19+(20-x)]
-
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
-
1/2x+3=1/3x+2 0.5x-0.7=6.5+0/2x 1-7/3x=2/3x+19 0.4x-1/4=8-1/
-
计算:1/x(x-1)+1/(x-1)(x-2)+1/(x-2)(x-3)+.+1/(x-19)(x-20)
-
19.解方程.3-5x=2x+9 20.解方程.7(2x-1)-3(4x-1)=4(3x+2)-1