问题标题:
【求下列极限1.limx→0y→2sin(xy)/x2.limx→0y→0(2-√(xy+4))/xy3.limx→0y→0(x^2y)/(x^3-y^3)4.limx→0y→1xy*sin(1/(x^2+y^2))】
问题描述:
求下列极限1.limx→0y→2sin(xy)/x2.limx→0y→0(2-√(xy+4))/xy
3.limx→0y→0(x^2y)/(x^3-y^3)4.limx→0y→1xy*sin(1/(x^2+y^2))
葛声回答:
1
limx→0y→2sin(xy)/x
=limx→0y→2(xy)/x
=limx→0y→2y
=2
2
limx→0y→0(2-√(xy+4))/xy
=limx→0y→0(4-(xy+4))/[(xy)·(2+√(xy+4))]
=limx→0y→0-(xy)/[(xy)·(2+√(xy+4))]
=limx→0y→0-1/[(2+√(xy+4))]
=-1/4
刘荣荣回答:
3.limx→0y→0(x^2y)/(x^3-y^3)4.limx→0y→1xy*sin(1/(x^2+y^2))帮助看看,谢谢。
葛声回答:
3.令y=kx,则原式=limx→0(kx^3)/(x^3-k^3·x^3)=k/(1-k^3)随着k值变化极限值也发生变化,因此极限不存在4.=0,没啥说的