lim(x^2+y^2)sin(1/(x^2+y^2))X趋向0，Y趋向0 求此极限

lim(x(sin)^2) lim sin(y×x^2+y^4)/(x^2+y^2) x,y都趋于0， lim(sin(x^2*cos(1/x)))/x怎么做? lim(x趋向0)ln(1+sin x)/x^2 求极限lim(x-->0)x^2 sin(1/x), 求极限 lim sin(x^2 * sin (1/x))/x x->0求极限 lim sin(x^2 * sin (1/x))/x x->0 计算lim(x,y)→（2,2）sin[(x-1)^2-(y-1)^2]/(x-y) lim(x^2+y^2)sin(1/(x^2+y^2))X趋向0，Y趋向0 求此极限 (lim→-1)sin(x+1)/2(x+1) 求极限：lim(x*sin(1/x))^2 lim x->0(sqrt(sin(1/x^2)) 求极限 试证明极限 lim(x^2*y^2)/(x^2*y^2+(x-y)^2)不存在还有一题 计算二重极限lim(x^2+y^2)sin(1/(x^2+y^2))x→0，y→0 lim x(x+2)/x^2 (x→oo)lim 1/sin(x-2) (x→2) 求 lim(x→1)sin(x+1)/x+1 求 lim(x→2)x²-4/x-2 x→2,y→0,求lim sin[(8 -x)y]/xy=多少呀? 求极限 （（sin(x^3+x^2-x)+sin x) /x x→0 已知lim sinx/x=1 lim(x---1)[sin^2(x)-sin^2(1)]/[x-1]=?大学高等数学,求教. 请教一道函数极限问题：lim[sin√（x^2+1)-sin(x)] (x→+∞)