已知实数满足a2+3a-2=0,求1a+1-a+2a2-1×a2-2a+1a2+4a+4的值.-数学

题目简介

已知实数满足a2+3a-2=0,求1a+1-a+2a2-1×a2-2a+1a2+4a+4的值.-数学

题目详情

已知实数满足a2+3a-2=0,求
1
a+1
-
a+2
a2-1
×
a2-2a+1
a2+4a+4
的值.
题型:解答题难度:中档来源:不详

答案

class="stub"1
a+1
-class="stub"a+2
a2-1
×
a2-2a+1
a2+4a+4

=class="stub"1
a+1
-class="stub"a+2
(a-1)(a+1)
×
(a-1) 2
(a+2) 2

=class="stub"1
a+1
-class="stub"a-1
(a+1)(a+2)

=class="stub"a+2-a+1
(a+1)(a+2)

=class="stub"3
a 2+3a+2

∵a2+3a-2=0,
∴a2+3a=2,
∴原式=class="stub"3
2+2
=class="stub"3
4

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