limx→1(1x2-3x+2-2x2-4x+3)=()A.-12B.12C.-16D.16-数学

题目简介

limx→1(1x2-3x+2-2x2-4x+3)=()A.-12B.12C.-16D.16-数学

题目详情

lim
x→1
1
x2-3x+2
-
2
x2-4x+3
)=(  )
A.-
1
2
B.
1
2
C.-
1
6
D.
1
6
题型:单选题难度:中档来源:陕西

答案

lim
x→1
class="stub"1
x2-3x+2
-class="stub"2
x2-4x+3

=
lim
x→1
[class="stub"1
(x-2)(x-1)
-class="stub"2
(x-1)(x-3)
]

=
lim
x→1
class="stub"1-x
(x-1)(x-2)(x-3)

=
lim
x→1
class="stub"-1
(x-2)(x-3)

=-class="stub"1
2

故选A.

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