求极限 （x2+y2）^(x2y2) x,y都趋于0我知道答案为1

求极限 （x2+y2）^(x2y2) x,y都趋于0我知道答案为1 求极限lim(x,y)→(0,0) [1-cos(x2+y2)]/[(x2+y2)e^x2y2] 已知实数x,y满足x2+y2=2x,求x2y2的范围 已知:x-y= -2 求(x2+y2)2-4xy(x2+y2)+4x2y2的值 设x2y2-20xy+x2+y2+81=0,求x+y的值 已只x+y=a,x2+y2=b求4x2y2=? 已知x=y=a,x2=y2=b求4x2y2=? 化简求值（2X2-2y2）-3（X2y2+X2）+3（X2y2+y2）,其中X=-1,y=2 （2x2-2y2）-3（x2y2+x2）+3x2y2+y2.提示：x=-1,y=2 化简求值 已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以（x2+y2/xy）2乘1/x+y的值 因式分解x2y2-x2-y2+1 X2y2-x2-y2+1因式分解. 若X2-2X+Y2-4Y+5=0,求9X2Y2-12X3Y2+4X4Y2的值 已知xy/x+y=1/3,x2y2/x2+y2=1/5,求xy的值. 已知x2+y2-4x-10y+29=0求x2y2+2x3y2+x4y2的值 已知x.y为正整数,且满足2x2+3y2=4x2y2+1,求x2+y2的值过程 整数x,y满足方程15x2y2=35x2-3y2+412,则有15x2y2= lim(x,y)→(0,0)(1-cos(x2+y2))/(x2+y2)x2lim(x,y)→(0,0)(1-cos(x2+y2))/(x2+y2)x2y2