(1)(2008-π)0+(13)-1-2cos45°;(2)当x=-13时,求(3xx-1-xx+1)÷xx2-1的值.-数学

题目简介

(1)(2008-π)0+(13)-1-2cos45°;(2)当x=-13时,求(3xx-1-xx+1)÷xx2-1的值.-数学

题目详情

(1)(2008-π)0+(
1
3
)
-1
-
2
cos45°

(2)当x=-
1
3
时,求(
3x
x-1
-
x
x+1
x
x2-1
的值.
题型:解答题难度:中档来源:不详

答案


(1)(2008-π)0+(class="stub"1
3
)-1-
2
cos45°

=1+3-1
=3;

(2)(class="stub"3x
x-1
-class="stub"x
x+1
)÷class="stub"x
x2-1

=3(x+1)-(x-1)
=2x+4.
当x=-class="stub"1
3
时,
原式=-class="stub"2
3
+4=class="stub"10
3

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