高一函数若logab=logba若logab=logba(a≠b
若logab=logba(a≠b,a≠1,a≠1)则ab= A.1 B.2 .1/4 D.4
log(a)[b]=log(b)[a] lgb/lga=lga/lgb [(lgb)²-(lga)²]/lgalgb=0 (lga-lgb)(lga+lgb)=0 a≠b lga+lgb=lgab=0 ab=1 选A