∵角A,B,C成等差数列,
∴a+a+d+a+2d=180°
a+d=60°
∠B=60°
∵sinA,sinB,sinC成等差数列,sinB=√3/2
2sinB=sinA+sinC
√3=sinA+sinC
√3=sin[π-(B+C)]+sinC
sin(B+C)+sinC=√3
sinBcosC+cosBsinC+sinC=√3
√3/2cosC+1/2sinC+sinC=√3
√3/2cosC+3/2sinC=√3
1/2cosC+√3/2sinC=1
sin(C+π/6)=1
C+π/6=π/2
C=π/3=60°
∴该三角形为等边三角形