求lim(x→0,y→1)(1-xy)/(x2+y2)=____

求极限lim(x,y)→(0,0) 3xy/(xy+4)^1/2-2 当x→0 y→1时 求lim(1-xy)/x²+y² 求下列各极限 lim(x,y)→(0,1) (2-xy)/(x^2+2y) lim(x,y)→(0,1) (1+xy)^1/x 求大神帮忙,谢谢～ 求lim(x→0,y→1)(1-xy)/(x2+y2)=____ 求lim（x→0,y→0） ysin(1/xy)的极限 跪求极限Y=lim (xy+1)/x^4+y^4,当（x,y）→（0,0）, 求极限Y=lim (xy+1)/x^4+y^4,当（x,y）→（0,0）, 求二重极限lim[xy/(1+x^2+y^2)],x→0,y→0.求详细步骤 求极限lim(x,y)→(0,0) [1-cos(xy)]/xy^2.求极限lim(x,y)→(0,0) [1-cos(xy)]/xy^2,麻烦写下过程 求极限lim(x,y)→(0,0) [1-cos(xy)]/xy^2求极限lim(x,y)→(0,0) [1-cos(xy)]/xy^2,麻烦写下过程 求极限lim(x→1 y→2) (x²+y²)/xy 两重极限题 求 lim(x,y)→(0,0)(1+xy)^(1/(x+y))的极限求lim(x,y)→(0,0)(1+xy)^(1/(x+y))的极限答案是不存在 求详解 求极限lim x→0 y→0 2xy/根号下1+xy 然后-1 {不在根号里｝ 求极限:lim xy分之{[(1+xy)开3次根号]-1},(x,y)→(0,0)$(acontent) 如何求Lim[2-(xy+4)^1/2]/xy x→0 ,y→0 和Lim sin(xy)/x x→0,y→0 这两道的极限值,求解题过程!谢谢 求下列极限 1.lim x→0y→2 sin(xy)/x 2.lim x→0y→0 (2-√（xy+4）)/xy3.lim x→0y→0(x^2y)/(x^3-y^3) 4.limx→0y→1 xy*sin(1/(x^2+y^2)) 高数:lim(x→0,y→0)2XY/(XY-1)开根-1