a/sinA=b/sinB=c/sinC=k
(a-c)(sinA+sinC)=(a-b)sinB
(a-c)(a+c)=(a-b)b
a^2+b^2-ab=c^2
2cosC=1
c=60
sinA+sinB=2sin(A+B)/2cos(A-B)/2=√3cos(A-B)/2
A=B=60最大值√3
a/sinA=b/sinB=c/sinC=k
(a-c)(sinA+sinC)=(a-b)sinB
(a-c)(a+c)=(a-b)b
a^2+b^2-ab=c^2
2cosC=1
c=60
sinA+sinB=2sin(A+B)/2cos(A-B)/2=√3cos(A-B)/2
A=B=60最大值√3