已知1/1×2=1-1/2,1/2×3=1/2-1/3,1/3×4=1/3-1/4.,则1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)

来源：学生作业帮助网编辑：作业帮时间：2024/11/06 07:11:37

已知1/1×2=1-1/2,1/2×3=1/2-1/3,1/3×4=1/3-1/4.,则1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)
已知1/1×2=1-1/2,1/2×3=1/2-1/3,1/3×4=1/3-1/4.,则1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)

已知1/1×2=1-1/2,1/2×3=1/2-1/3,1/3×4=1/3-1/4.,则1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)
1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)
=1/x-1/(x+1)+1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)
=1/x-1/(x+3)

原式=1/x-1/(x+1)+1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)
=1/x-1/(x+3)
=3/<(x+3)*x>

1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)
=1/x-1/(x+1)+1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)=1/x-1/(x+3)=3/[x(x+3)]
此题就是利用拆项达到把中间项相互抵消消项的目的,1/n*m=(1/n-1/m)/(m-n),m>n

已知sinx=1/3,2π 已知sinx=1/3,2π 已知cosa=1/3,且-/2 已知cosx=1/3,-派/2 已知sinx=1/3(2π 已知sina=1/3,2pai 已知2分之1 已知-1/2 已知-1/2 已知2（1-x) 已知1/2 已知1/2 已知2（a+1) 1、已知2 已知x+1/2 已知1/2 已知y=kx+3,已知定义域[1k,2k],求值域? 已知已知4^4x+1=8^2x+3,求x的值