sin²B-sin²C-sin²A=√3sinAsinC在⊿ABC中,由正弦定理知,a/sinA=b/sinB=c/sinC=2R.===>sinA=a/2r.sinB=b/2R.sinC=c/2R.∴由sin²B-sin²C-sin²A=(√3)sinAsinC可得:（b/2R)²-(c/2R)...