lg25+2/3lg8+lg5*lg20+（lg2）^2=?

分类: 作业答案 • 2021-12-20 05:59:09

问题描述：

答

=2lg5+2lg2+lg5*(1+lg2)+(lg2)^2
=2(lg5+lg2)+lg5+lg5*lg2+(lg2)^2
=2+lg5+lg2*(lg5+lg2)
=2+lg5+lg2
=2+1
=3

答

原式=2lg5+2lg2 +lg5(lg5+2lg2)+(lg2)^2
=2(lg5+lg2)+(lg2)^2+2lg2lg5+(lg5)^2
=2lg10+[lg2+lg5]^2
=2+1^2
=2+1
=3