问题
解答题
(1)化简与求值:(0.0081)-
(2)化简与求值:log2
|
答案
(1)(0.0081)-
-[3(1 4
)0]-1•[81-0.25+(7 8
)-27 8
]-1 3
-10×0.0271 2 1 3
=[(0.3)4]-
-3-1•[(34)-1 4
+(1 4
)-1]-3 2
-10×(0.33)1 2 1 3
=
-10 3
×(1 3
+1 3
)-2 3
-31 2
=
-10 3
-3=0;1 3
(2)log2
+log212-7 48
log242-11 2
=
log21 2
+log212-7 48
log242-11 2
=
(log21 2
-log242)+log212-17 48
=
log21 2
+log212-11 288
=-
log22×122+log212-11 2
=-
(1+2log212)+log212-11 2
=-
-1=-1 2
.3 2