根据正弦定理b/a=sinB/sinA a/b=sinA/sinBb/a+a/b=sinB/sinA+sinA/sinB=(sin²A+sin²B)/sinAsinB=1/sinAsinB=4cosC1/tanA+1/tanB=cosA/sinA+cosB/sinB=sin(A+B)/sinAsinB=sinC/sinAsinB=4sinCcosC=2sin2C0∴0<2sin2C<=2貌似只有最大值并为2没有最小值啊
