问题 解答题
计算:
(1)(2
1
4
)
1
2
-(-
1
8
)0-(3
3
8
)-
2
3
+(1.5)-2+
(1-
2
)
2

(2)已知log73=a,log74=b,求log4948.(其值用a,b表示)
答案

(1)原式=(

9
4
)
1
2
-1-(
27
8
)-
2
3
+(
3
2
)-2+|1-
2
|

=[(

3
2
)2]
1
2
-1-[(
3
2
)3]-
2
3
+
4
9
+
2
-1

=

3
2
-1-
4
9
+
4
9
+
2
-1

=

2
-
1
2

(2)

log4948=
1
2
log7(3×16)=
1
2
(log73+log716)
=
1
2
(log73+2log74)

=

1
2
(a+2b).

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