(lg2)*(lg2)+lg5*lg20-1怎么计算
问题描述:
(lg2)*(lg2)+lg5*lg20-1怎么计算
答
(lg2)²+lg5×lg20-1
=(lg2)²+lg5×(lg10+lg2)-1
=(lg2)²+lg5×(lg2+1)-1
=(lg2)²+lg5lg2+lg5-1
=lg2(lg2+lg5)+lg5-1
=lg2 +lg5-1
=0