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> 先化简,再求值:xx2-1÷(1+1x-1),其中x=2cos30°-(3)0.-数学
先化简,再求值:xx2-1÷(1+1x-1),其中x=2cos30°-(3)0.-数学
题目简介
先化简,再求值:xx2-1÷(1+1x-1),其中x=2cos30°-(3)0.-数学
题目详情
先化简,再求值:
x
x
2
-1
÷(1+
1
x-1
)
,其中x=2cos30°-(
3
)
0
.
题型:解答题
难度:中档
来源:咸宁
答案
class="stub"x
x
2
-1
÷(1+
class="stub"1
x-1
)=
class="stub"x
x
2
-1
÷
class="stub"x-1+1
x-1
=
class="stub"x
(x+1)(x-1)
×
class="stub"x-1
x
=
class="stub"1
x+1
.
x=2cos30°-(
3
)0=2×
3
2
-1=
3
-1
.
∴当
x=
3
-1
时,
原式=
class="stub"1
x+1
=
class="stub"1
3
-1+1
=
class="stub"1
3
=
3
3
.
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题目简介
先化简,再求值:xx2-1÷(1+1x-1),其中x=2cos30°-(3)0.-数学
题目详情
答案
=
=
x=2cos30°-(
∴当x=
原式=