Question

(lg2)^2+lg20*lg5+(lg5)^2

Answer 1

原式＝(lg2)^2+lg(5*2^2)*lg5+(lg5)^2

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

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

=(lg2+lg5)^2+(lg5)^2

=1+(lg5)^2