lg2lg50+lg5×lg20-lg100×lg5×lg2=
问题描述:
lg2lg50+lg5×lg20-lg100×lg5×lg2=
答
lg2lg50+lg5lg20-lg100lg5lg2
=lg2(lg2+2lg5)+lg5(2lg2+lg5)-2lg2lg5
=(lg2)^2+2lg2lg5+(lg5)^2
=(lg2+lg5)^2
=(lg10)^2
=1