lg5乘以lg8000 等于多少?
问题描述:
lg5乘以lg8000 等于多少?
答
lg5=1-lg2
lg8000=lg8+3=3lg2+3=3(1+lg2)
lg5·lg8000
=(1-lg2)[3(1+lg2)]
=3-3(lg2)^2