1-2sinx*sin(60+x)sin(60-x)=1-2sinx[(sin60cosx+cos60sinx)*(sin60cosx-cos60sinx)]=1-2sinx(sin²60cos²x-cos²60sin²x)=1-2sinx（3/4cos²x-1/4sin²x）=1-1/2 sinx（3cos²x-sin&...