f(x,y) = x^2y/(x^2+y^2),0 ≤ | f(x,y) | = x²/(x²+y²) * |y| ≤ |y|lim(x,y)->(0,0) |y| = 0,利用迫敛准则,lim |f(x,y)| = 0,∴ lim f(x,y) = 0 = f(0,0)故此函数在(0,0)处连续.注：计算二重极限,...