计算或化简求值(1)|3-2|-(-2)2+2sin60°; (2)先化简:xx+2-x2+2x+1x+2÷x2?1x?1,其中x=3-2
计算或化简求值(1)|3-2|-(-2)2+2sin60°;(2)先化简:xx+2-x2+2x+1x+2÷x2?1x?1,其中x=3-2....
计算或化简求值(1)|3-2|-(-2)2+2sin60°; (2)先化简:xx+2-x2+2x+1x+2÷x2?1x?1,其中x=3-2.
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(1)解:原式=2-
-4+2×
=2-
-4+
=-2;
(2)
-
÷
=
-
×
=
-
=
,
当x=
-2时,原式=
3 |
| ||
2 |
=2-
3 |
3 |
=-2;
(2)
x |
x+2 |
x2+2x+1 |
x+2 |
x2?1 |
x?1 |
=
x |
x+2 |
(x+1)2 |
x+2 |
x?1 |
(x+1)(x?1) |
=
x |
x+2 |
x+1 |
x+2 |
=
?1 |
x+2 |
当x=
3 |
?1 | |
|