求下列各式的极限．
(1)limx→0,y→0xy/(√1+xy)-1；
(2)limx→0,y→0sinxy/x
(1)limx→0,y→0xy/(√1+xy)= limx→0,y→0xy((√1+xy)+1)/(1+xy-1)= limx→0,y→0[(√1+xy)+1] (2)limx→0,y→0sinxy/x=limx→0,y→0(sinxy/xy)y=1•0=0．
求下列各式的极限．
(1)limx→0,y→0xy/(√1+xy)-1；
(2)limx→0,y→0sinxy/x
(1)limx→0,y→0xy/(√1+xy)= limx→0,y→0xy((√1+xy)+1)/(1+xy-1)= limx→0,y→0[(√1+xy)+1] (2)limx→0,y→0sinxy/x=limx→0,y→0(sinxy/xy)y=1•0=0．
