问题
解答题
计算下列各式: (Ⅰ)(lg2)2+lg5lg20-1; (Ⅱ)2-(
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答案
(Ⅰ)原式=lg22+(1-lg2)(1+lg2)-1(2分)
=lg22+1-lg22-1=0(3分)
(Ⅱ)原式=
-(2
+1)+22
×3
×6 12
(1分)3 3 2
=-1+2×3
×21 2
×(1 6
)3 2
(2分)1 3
=-1+×21+
-2 6
×31 3
+1 2
+1 6
=5.(2分)1 3