tan10tan20+tan20tan60+tan60tan10=tan10tan20+√3(tan20+tan10)因为tan(30)=tan(20+10)=(tan20+tan10)/[1-tan20tan10]=√3/3tan20+tan10=√3/3*[1-tan20tan10]故：tan10tan20+tan20tan60+tan60tan10=tan10tan20+√3...