2lg5+3分之2lg8+lg5乘lg20+(lg2)^2

分类: 作业答案 • 2021-12-20 05:59:33

问题描述：

答

2lg5 +(2lg8)/3 +lg5*lg20 +(lg2)^2
=lg5[2+lg(2*10)]+2lg2+(lg2)^2
=lg5(3+lg2)+lg2(2+lg2)
=lg5 +(2+lg2)(lg5+lg2)
=lg5+lg2+2
=3

答

lg5^2+2/3lg8+lg5*lg20+(lg2)^2
=2lg5+2/3lg2^3+lg5*lg(4*5)+(lg2)^2
=2lg5+2lg2+(lg5)^2+lj5*2lg2+)lg2)^2
=2(lg2+lg5)+(lg2+lg5)^2
=2lg10+lg10^2
=2+1
=3