已知㏒ab=㏒ba(a>0≠1,b>0且≠1)求证a=b或a=1/b
问题描述:
已知㏒ab=㏒ba(a>0≠1,b>0且≠1)求证a=b或a=1/b
答
㏒ab=㏒ba=1/LOG(A,B)
==>(LOG(A,B))^2=1
==>LOG(A,B)=1 或者 LOG(A,B)=-1
==>A=B 或者B=A^(-1)==> A=1/B