log₂1.25+log₂0.2
=log₂(1.25×0.2)
=log₂0.25
=log₂(1/2)²
=-2倒数第二个不懂？为什么是log2(1/2)的2次方呀？？？？？而且怎么就等于-2了呢log₂1.25+log₂0.2=log₂(1.25×0.2)=log₂0.25=log₂(1/4)=log₂(1/2)²=log₂2^(-2)=-2