设函数(x)=lim _(narrow infty )dfrac ({x)^n+3}(sqrt {{3)^2n+(x)^2n}}(-infty lt xlt +infty )，则(x)=lim _(narrow infty )dfrac ({x)^n+3}(sqrt {{3)^2n+(x)^2n}}(-infty lt xlt +infty )在区间(x)=lim _(narrow infty )dfrac ({x)^n+3}(sqrt {{3)^2n+(x)^2n}}(-infty lt xlt +infty )上()A.连续B.有一个可去间断点C.有一个跳跃间断点D.有一个第二类间断点

设(x)=lim _(narrow infty )dfrac ({x)^n+2}(sqrt {{2)^2n+(x)^2n}}，则(x)=lim _(narrow

设 (x)=lim _(narrow infty )dfrac ({x)^n+2-(x)^-n}({x)^n+(x)^-n} 则函数(x)=lim _(narr

(2)设函数 (x)=lim _(narrow infty )sqrt [n](1+{|x|)^3n}, 则 f(x)在 (-infty ,+infty ) 内

→(a)→∞-|||-lim _(narrow infty )(x)_(n)=+infty lim _(narrow infty )(y)_(n)=infty

(2)设函数 (x)=lim _(narrow infty )sqrt [n](1+{|x|)^3n} 则 f(x)在 (-infty ,+infty ) 内

设(x)=lim _(narrow infty )dfrac ({x)^2n-1+a(x)^2+bx}({x)^2n+1}-|||-+bx/，若(x)=lim

已知 lim _(narrow infty )(a)_(n)=2 lim _(narrow infty )(b)_(n)=3已知 lim _(narrow in

(3) lim _(narrow infty )dfrac (sqrt {{n)^2-3n}}(2n+1)

例4:讨论函数 (x)=lim _(narrow infty )dfrac ({x)^n+2-(x)^-n}({x)^n+(x)^-n} 的间断点及其类型.

设函数 f(x)= lim_(n to infty) (1 + x)/(1 + x^2n)，则下列结论成立的是(）A. $f(x)$ 无间断点B. $f(x)$