sin105°= sin（45°+60°）= sin45°cos60°+cos45°sin60°= √2/2*½+√2/2*√3/2= √2/4+√6/4= （√2+√6）/4sin75°= sin（45°+30°）= sin45°cos30°+cos45°sin30°= √2/2*√3/2+√2/2*½= （√2...