因为x^2/4+y^2/9=1所以(x/2)^2+(y/3)^2=1,运用三角换元法：因为sin^2a+cos^2a=1所以设x/2=sina,y/3=cosax=2sina,y=3cosa,因为p(x,y)在椭圆上,所以：x+y=2sina+3cosa==√(3²+2²)sin(θ+φ)≤√13...