在三角形ABC中,角A,B,C所对的边为a,b,c,且（b^2-a^2-c^2）/ac=cos(A+C)/sinAcosA,若sinB/cosC>根号2,

(b^2-a^2-c^2)/ac=-2cosB
cos(A+C)/sinAcosA=-cosB/(sinAcosA)
2sinAcosA=1
sin2A=1
A=π/4
sinB/cosC=sin(A+C)/cosC=sinA+cosAsinC/cosC>√2
sinC/cosC>1
C的范围是(π/4,π/2)