计算:(lg2)的平方+lg5乘以lg20减去1

问题描述:

计算:(lg2)的平方+lg5乘以lg20减去1

lg2)^2+lg5*lg20-1
=(lg2)^2+lg5lg(4*5)-1
=(lg2)^2+lg5(lg2^2+lg5)-1
=(lg2)^2+lg5*lg2^2+(lg5)^2-1
=(lg2)^2+2lg5*lg2+(lg5)^2-1
=(lg5+lg2)^2-1
=(lg10)^2-1
=1-1
=0