高一计算题

(lg2)²+lg5.lg20-1注:lg5.和lg20中间代表的是乘号
2025-12-17 03:07:12
推荐回答(3个)
回答1:

原式=(lg2)²+lg5.(lg5+2lg2)-1
=(lg5+lg2)^2-1
=0

回答2:

(lg2)²+lg5.lg20-1
=(lg2)²+lg5(lg2+lg10)-1
=(lg2)²+lg5*lg2+lg5-1
=lg2(lg2+lg5)+lg5-1
=lg2+lg5-1
=lg10-1
=1-1
=0

回答3:

lg2*lg2+lg5*(lg5+lg4)-1
=lg2*lg2+lg5*lg5+2lg5*lg2-1
=(lg2+lg5)平方-1
=1-1
=0