a=log(1/2)^10 b=log(20)^10 1/a+1/b=

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a=log(1/2)^10 b=log(20)^10 1/a+1/b=

a=log(1/2)^10 b=log(20)^10 1/a+1/b=
a=log(1/2)^10 b=log(20)^10 1/a+1/b=

a=log(1/2)^10 b=log(20)^10 1/a+1/b=

a=lg(1/2)/lg10
=lg(1/2)
=lg1-lg2
=-lg2
b=lg20/lg10
=lg20
=lg(2X10)
=lg2+lg10
=lg2+1
所以1/a+1/b
=1/(-lg2)+1/(lg2+1)
=-1/〔lg2(lg2+1)〕
后面自己查表吧