lg2=a,lg3=b,则lg√15的值是多少?
问题描述:
lg2=a,lg3=b,则lg√15的值是多少?
答
(1)lg6=lg2+lg3=a+b (2)log3(3为底数)4 =2log3(3为底数)2 =2lg2/lg3 =2a/b (3)log2(2为底数)12 =log2(2为底数)4+log2(2为底数)3 =2+log2(2为底数)3 =2+lg3/lg2 =2+b/a (4)lg3/2=lg3-lg2=b-a