y=lgX+4/(logx-1)

问题描述:

y=lgX+4/(logx-1)

y=lgX+4/(logx-1)
=lgX-1+4/(logx-1)+1
>=2*√(lgX-1)*4/(logx-1)+1
=4+1
=5
前提是:lgx-1>0
x>10是的,但还有x