Question

若a,b∈R,则使|a|+|b|>1成立的充分不必要条件是

A |a+b|≥1 B |a|≥1/2且|b|≥1/2 C |a|≥1 D b<-1

Answer 1

令k=a^lgblgk=lga^lgb=lgb*lga=lga*lgb=lgb^lga所以k=b^lga所以a^lgb=b^lga