求极限lim(xy)^2/(x^2+y^2)^2,(x,y)趋于（0,0）

求极限lim(x,y)→(+∞,+∞) [(xy)/(x^2+y^2)]^xy.求极限lim(x,y)→(+∞,+∞) [(xy)/(x^2+y^2)]^xy, 求极限：lim (x^2+y^2)^xy（x,y）lim (x^2+y^2)^xy x,y→0 这个极限是多少啊!怎么算? lim(xy/(x^2+y^2))^x^2 x,y趋近无穷 求极限 求极限lim(x,y)→(+∞,+∞) (xy/(x^2+y^2))^x^2 求极限lim(x,y)→(0,0) 3xy/(xy+4)^1/2-2 lim[sin(xy)/xy],x趋向2,y趋向0,求极限 求极限lim(xy)^2/(x^2+y^2)^2,(x,y)趋于（0,0） 求下列各极限 lim(x,y)→(0,1) (2-xy)/(x^2+2y) 求极限 lim((x,y）→（0,0)) (x^2+y^2)sin1/xy 求lim(x,y)~(0,1)1-xy/x^2+y^2的极限,要详解 求极限lim(x→1 y→2) (x²+y²)/xy 求极限lim（x,y）→（0,0）3-根号下（xy+9）/2xy求极限 求极限. lim (x→0) [√ (xy+4) -2 ]/xy (y→0)lim (x→0)(y→0)[√ (xy+4) -2 ]/xy 求二元函数极限：（x,y)趋近于(2,-1/2)时lim(2+xy)^(1/(y+xy^2)) 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→0 y→0 2xy/根号下1+xy 然后-1 {不在根号里｝