1/[(sinx+1/2)^2+(cosx+1/2)^2-1/2] {X^2 为X的2次方}(sin x+1/2)^2+(cos x+1/2)^2 -1/2≥ 2(sin x+1/2)(cos x+1/2)-1/2 {均值不等式}=2*sin x *cos x+sin x+cos x+1/2-1/2=2*sin x *cos x+sin x+cos x+1-1=(sin x +...