唔..sos...数学达人请...头晕ing..
问题描述：
唔..sos...数学达人请...头晕ing..
取lg2=0.3010,则lg2.5=_____
偶基道答案是0.3980..but只会一半- -1汗
呜..刚学对数`那个叫晕菜...题目它认识咱,咱不认识它- -1
..教下呢～感激ing...
答
1
lg2.5
=lg(5/2)=lg5-lg2=1-2lg2=1-2*0.3010=0.3980
补充：
lg2+lg5=1
lg(a/b)=lga-lgb