问题
解答题
计算下列各式: (1)
(2)2(lg
|
答案
(1)
=(a
•b-1)-,2 3
•a1 2
•b1 2 1 3 6 a•b5
=a-
b1 3
•a1 2
•b1 2 1 3 a
b1 6 5 6
=1a
b1 6 5 6 a
b1 6 5 6
(2)2(lg
)2+lg2
•lg5+2 (lg
)2-lg2+12
=2(lg2
)2+lg21 2
•lg5+1 2 (lg2
)2-lg2+11 2
=2(
lg2)2+1 2
lg2•lg5+1 2 (
lg2)2-lg2+11 2
=2(
lg2)2+1 2
lg2•lg5+1 2 (
lg2-1)21 2
=
lg2(lg2+lg5)+|1 2
lg2-1|1 2
=
lg2•lg(2•5)+1-1 2
lg21 2
=
lg2+1-1 2
lg2=11 2