lg5*lg5+2/3lg8+lg5*lg20求值,

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lg5*lg5+2/3lg8+lg5*lg20求值,
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lg5*lg5+2/3lg8+lg5*lg20求值,
lg5*lg5+2/3lg8+lg5*lg20
求值,

lg5*lg5+2/3lg8+lg5*lg20求值,
(2/3)lg(8)=(2/3)lg(2³)=2lg2
则:
原式=[lg5]²+2lg2+lg5×[lg2+lg10]
. =[lg5]²+2lg2+lg5×[1+lg2]
. =[lg5]²+2lg2+lg5+lg2×lg5
. =lg5[lg2+lg5]+2lg2+lg5
. =lg5+2lg2+lg5
. =2lg5+2lg2
. =2[lg2+lg5]
. =2

这没法算啊。。
你题应该是打错了吧
应该是lg5²+(2/3)lg8+lg5*lg20+(lg2)²吧
lg5²+(2/3)lg8+lg5*lg20+(lg2)²
=lg5²+2/3lg8+lg5×lg20+(lg2)²
=2lg5+2/3lg2³+lg5×lg(4×5)+(lg2)...

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这没法算啊。。
你题应该是打错了吧
应该是lg5²+(2/3)lg8+lg5*lg20+(lg2)²吧
lg5²+(2/3)lg8+lg5*lg20+(lg2)²
=lg5²+2/3lg8+lg5×lg20+(lg2)²
=2lg5+2/3lg2³+lg5×lg(4×5)+(lg2)²
=2lg5+(2/3)×3lg2+lg5×(lg4+lg5)+(lg2)²
=2(lg5+lg2)+lg5×lg2²+(lg5)²+(lg2)²
=2lg(5×2)+2lg5×lg2+(lg5)²+(lg2)²
=2lg10+(lg5+lg2)²
=2+[lg(5×2)]²
=2+(lg10)²
=2+1²
=3

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