先化简再求值(X+1分子1-1-X分子1)÷X²-1分之1其中X等于2分之1_数学解答

先化简再求值(X+1分子1-1-X分子1)÷X²-1分之1其中X等于2分之1

人气：301 ℃　时间：2020-05-29 11:35:40

解答

[1/(X+1)-1/(1-X)]÷1/(X²-1)
=[1/(X+1)-1/(1-X)]x(X²-1)
=1/(X+1)x(X²-1)- 1/(1-X)x(X²-1)
=1/(X+1)x(X²-1)+ 1/(X-1)x(X²-1)
=(X-1)+(X+1)
=X-1+X+1
=2X
=2*1/2
=1