Question Number 156065 by VIDDD last updated on 07/Oct/21
$$\:\mathrm{find}\:\mathrm{the}\:\mathrm{minimum}\:\mathrm{of}\:\mathrm{expression}\:\mathrm{M}=\boldsymbol{\mathrm{cos}}\frac{\boldsymbol{\mathrm{A}}−\boldsymbol{\mathrm{B}}}{\mathrm{2}}\mathrm{sin}\frac{\boldsymbol{\mathrm{A}}}{\mathrm{2}}\mathrm{sin}\frac{\boldsymbol{\mathrm{B}}}{\mathrm{2}} \\ $$