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))

求下列极限:lim[(x,y)→(0,0)][1/(x^2+y^2)] 求下列各极限 lim(x,y)→(0,1) (2-xy)/(x^2+2y) 求下列极限lim(x→0)(1-cosx)/xsinx lim(x→0y→1)(1+xe^y)^(2y+x/x)求极限 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? 证明下列极限不存在 lim(x→0,y→0) （X+Y)/(X-Y) 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)) 求下列极限,lim(x+2sinx)/(x+3sinx),x→0烦请给出具体步骤, 用洛必达法则求下列极限(1)lim(x→0^＋)lntan7x/lntan2x(2)lim(x→0)xcot2x 求极限lim(x→0,y→0)xln(x^2+y^2)的值? 求极限 lim((x,y）→（0,0)) (x^2+y^2)sin1/xy 求下列极限 lim(x→0) (sinx-xcosx)/(sinx*x^2) 求下列极限,lim e^(1/2x),x→0烦请给出具体步骤, 求极限lim(x→+∞,y→+∞) (X+Y)/(X^2-Y^2) lim((x-y)/(x+y))求极限.(x,y)→(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,y）→（0,0）3-根号下（xy+9）/2xy求极限 lim 2x/tan3x x→0 求极限