用换底公式原式=(lg3/lg4+lg3/lg8)*(lg2/lg3)=(lg3/2lg2+lg3/3lg2)*(lg2/lg3)=(1/2+1/3)(lg3/lg2)(lg2/lg3)=5/6
=2log2(3)+3log2(3)*log3(2)=2log2(3)+3
