1/(x+10)+1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+9)(x+10)=2,x等于多少?
1个回答

你是不是写题目的时候少写了点东西?

如果按照你题目所写,可得:

1/(x+1)-1/(x+3)+1/(x+9)=2 (这个貌似很难解出x……)

如果你题目少写了省略号的话,那么题目应该是

1/(x+10)+1/(x+1)(x+2)+1/(x+2)(x+3)+……+1/(x+9)(x+10)=2

则有

1/(x+10)+1/(x+1)(x+2)+1/(x+2)(x+3)+……+1/(x+9)(x+10)

=1/(x+10)+{[1/(x+1)-1/(x+2)]+[1/(x+2)-1/(x+3)]+……+[1/(x+9)-1/(x+10)]}

=1/(x+10)+[1/(x+1)-1/(x+10)]

=1/(x+1)

所以1/(x+1)=2,x= -1/2