f(x) x趨于無窮時(shí),結(jié)果跟某一個(gè)數(shù)差為0,
f(x)/a =1; f(x)-a =0等等,找一個(gè)好做的做f(x,y),二元函數(shù)你能否給出個(gè)具體函數(shù)。lim|3x^2y/(x^2+y^2)|x,y 沒有趨于的范圍么？或者說x趨于無窮，結(jié)果趨于3|y| 算不算？趨向于(0,0)不好意思|3x^2y/(x^2+y^2)| = |3y/(1+(y/x)^2)|lim(|3y/(1+(y/x)^2)|) = 0