1 1 1 1 1—+ —+ —+ —+...+ ——1X2 2X3 3X4 4X5 199X200
1个回答
=1-1/2+1/2-1/3+1/3-1/4+……+1/199-1/200
=1-1/200
=199/200
相关问题
1 1 1 1 1 —— + —— +—— + —— + …… + ———— 1x2 2x3 3x4 4x5 199x2
(1-1/2)X(1-1/3)X(1-1/4).X(1-1/199)=?
计算:1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)+.+1/(x+2003)(x+200
1x2=1/3(1x2x3=0x1x2 ) 2x3=1/3(2x3x4-1x2x3) 3x4=1/3(3x4x5- 2x
1/(x+1)(x+2) + 1/(x+2)(x+3) + 1/(x+3)(x+4) + 1/(x+4)(x+5)
1/x-1+1/(x-1)(x-2)+1/(x-2)(x-3)+1/(x-3)(x-4)+1/(x-4)(x-5)
1x2=1|3(1x2x3-0x1x2) 2x3=1|3(2x3x4-1x2x3) 3x4=1|3(3x4x5-2x3x
4/5x+2=-1/3x-1.-5/6x+2=-1/3x-1.6(x-4)=-3(4+2x).
X-(1/4+3)-1/3{(X-1/4X+3)}-2-1/2{X-(X-1/4X+3)-1/3(X+1/4X+3)-2
x1+5x2-x3-x4=-1x1-2x2+x3+3x4=33x1+8x2-x3+x4=1