Question

问条对数计算题(lg 2)^2+lg 5*lg 20 -1=?

Answer 1

(lg 2)^2+lg 5*lg 20 -1

=(lg 2)^2+lg 5*lg （4*5）-1

=(lg 2)^2+lg 5*（lg 4+lg5）-1

=(lg 2)^2+lg 5*（2lg2+lg5）-1

=(lg 2)^2+lg 5*2lg2+lg5*lg5-1

=（lg2+lg5)^2-1

=1-1

=0