tan(A+B) =(tanA+tanB)/(1-tanAtanB)
=sqrt3*(tanAtanB-1)/(1-tanAtanB)
=-sqrt3
A+B =120°
sinAcosB =sqrt3 /4
sin(A+B) =sqrt3 /2 =sinAcosB +cosAsinB
即cosAsinB =sqrt3 /4
sin(A-B) =sinAcosB -cosAsinB =0
A=B=60°
所以C =60°
等边三角形
tan(A+B) =(tanA+tanB)/(1-tanAtanB)
=sqrt3*(tanAtanB-1)/(1-tanAtanB)
=-sqrt3
A+B =120°
sinAcosB =sqrt3 /4
sin(A+B) =sqrt3 /2 =sinAcosB +cosAsinB
即cosAsinB =sqrt3 /4
sin(A-B) =sinAcosB -cosAsinB =0
A=B=60°
所以C =60°
等边三角形