2lg 5+lg2*lg50=1

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2lg 5+lg2*lg50=1
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2lg 5+lg2*lg50=1
2
lg 5+lg2*lg50=1

2lg 5+lg2*lg50=1
=lg5*lg5+lg2(lg5+lg10)
=lg5*lg5+lg2(lg5+1)
=lg5*lg5+lg5*lg2+lg2
=lg5(lg5+lg2)+lg2
=lg5+lg2
=1

首先你要记得公式: a^[logc(b)]=b^[logc(a)]
这道题是这样的=lg5*lg5+lg2(lg5+lg10)
=lg5*lg5+lg2(lg5+1)
=lg5*lg5+lg5*lg2+lg2
=lg5(lg5+lg2)+lg2
=lg5+lg2
=1

lg5*lg5+lg2(lg5+lg10)
=lg5*lg5+lg2(lg5+1)
=lg5*lg5+lg5*lg2+lg2
=lg5(lg5+lg2)+lg2
=lg5+lg2
=1

=1