1,acosC+c/2=b
cosC=(2b-c)/2acosC=(a^2+b^2-c)^2/2ab
(2b-c)/2a =(a^2+b^2-c)^2/2ab
a^2+b^2-c^2=2b^2-bc
b^2+c^2-a^2=bc
cosA=(b^2+c^2-a^2)/2bc=bc/2bc=1/2
A=60B+C=120
2,a=1
b/sinB=a/sinAb=2√3sinB/3c=2√3sinC/3
a+b+c=2√3sinB/3+2√3sinC/3+1
=2√3/3*sinB+2√3/3*sin(120-B)+1
=2√3/3sinB+cosB+√3/3sinB+1
=√3sinB+cosB+1
=2*(√3/2*sinB+1/2*cosB)+1
=2sin(B+30)+10