问题
解答题
(1)计算:sin30°+2-1-(
(2)化简并求值:(1+
(3)解方程(
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答案
(1)原式=
+1 2
-1+2=2;1 2
(2)原式=
÷x-1+1 x-1 x2 (x+1)(x-1)
=
•x x-1 (x+1)(x-1) x2
=
,x+1 x
当x=
时,原式=2
=
+12 2
;2+ 2 2
(3)设y=
,则原方程可化为y2-y-2=0,x x+1
变形得:(y-2)(y+1)=0,
解得:y=2或y=-1,
∴
=2或x x+1
=-1,x x+1
解得:x=-2或x=-
,1 2
经检验,x=-2与x=-
都是原分式方程的解.1 2