两道初中数学题(1)化简分式(x^2-1/x^2+2x+1)-(x+1/x-1) (2)解方程(x-1/x)-(x/x-1)=5/2
问题描述:
两道初中数学题(1)化简分式(x^2-1/x^2+2x+1)-(x+1/x-1)
(2)解方程(x-1/x)-(x/x-1)=5/2
答
X^2-1/X^2+2X+1-X+1/X-1
=(X^2-1)(X-1)-(X+1)(X^2+2X+1)/(X^2+2X+1)(X-1)
=-5X^2+3X+2/(X+1)^2*(X-1)
=(5X+2)(1-X)/(X+1)^2*(X-1)
=5X+2/X^2+2X+1
答
(1)化简分式(x^2-1/x^2+2x+1)-(x+1/x-1) =(x+1)(x-1)/(x+1)^2-(x+1)/(x-1)=(x-1)/(x+1)-(x+1)/(x-1)=[(x-1)^2-(x+1)^2]/(x+1)(x-1)=-4x/(x+1)(x-1)(2)解方程(x-1/x)-(x/x-1)=5/2 (x-1)^2-x^2=5/2x(x-1)-2x+1=2.5...