Results of the Monte Carlo simulations on v sin i for red-arm LAMOST MRS. BT-Settl synthetic spectra with log g=4.5 and three different T_eff values, as indicated in the title of each box, have been adopted. The S/N=50. The average v sin i values measured with our procedure (dots) are plotted against the “theoretical” v sin i to which the spectra have been broadened. The error bars represent the standard deviations of the 200 simulations at each v sin i. The 1:1 relation is plotted with a dashed blue line.