一.设x=√3cosα,y=√3sinθ,m=cosθ,n=sinθ 则mx+ny=√3cosαcosθ+√3sinαsinθ=√3cos(α-θ)≤√3 二.(mx+ny)^2=m^2x^2+n^2y^2+2myxn≤m^2x^2+n^2y^2+m^2y^2+n^2x^2= (x^2)+(y^2)=3,(m^2)+(n^2)=1 两边分别相...