> 数学 >
(1)3−2−2cos45°+(
6
−3)0

(2)先化简,再求值:2a(a+b)-(a+b)2,其中:a=
2011
b=
2010
人气:142 ℃ 时间:2020-03-25 14:05:51
解答
(1)原式=
1
9
-2×
2
2
+1
=
1
9
-
2
+1
=
10
9
-
2

(2)原式=2a(a+b)-(a+b)2
=(a+b)(2a-a-b)
=(a+b)(a-b)
=a2-b2
a=
2011
b=
2010
时,原式=(
2011
2+(
2010
2=2011+2010=4021.
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