dfrac (1)(2)(S)_(8)^2-+(e)^-arrow (S)_(4)^2- (Na)^++dfrac (x)(4)(S)_(4)^2-+2(1-dfrac (x)(4))(e)^-(x)_(2)(S)_(x)-|||-钠电极-|||-a一-|||-电解质-|||-b 硫电极-|||-下列叙述错误的是-|||-A.充电时 ^+ 从钠电极向硫电极迁移-|||-B.放电时外电路电子流动的方向是 arrow b-|||-C.放电时正极反应为: (Na)^++dfrac (x)(8)(S)_(8)+2(e)^-arrow (Na)_(2)(S)_(x)-|||-D.炭化纤维素纸的作用是增强硫电极导电性能

(2)极限 lim _(xarrow infty )((1-dfrac {1)(2x))}^dfrac (x{2)}= () .-|||-(A)e (B) ^-

f(x)= ({e)^4-dfrac (1)(3))-|||-dfrac (1)(2)(e)^4-|||-dfrac (1)(2)((e)^2-dfrac

2.lim _(xarrow 0)(dfrac (2+{e)^dfrac (1{x)}}(1+{e)^dfrac (4{x)}}+dfrac (sin x)(|

2.求下列极限:-|||-(1) lim _(xarrow 4)dfrac ({x)^4-256}(x-4);-|||-(2) lim _(xarrow 0)d

下列选项中曲面dfrac ({x)^2}(4)+dfrac ({y)^2}(1)+dfrac ({z)^2}(9)=3上点dfrac ({x)^2}(4)+df

(4) lim _(xarrow -dfrac {1)(2)}dfrac (1-4{x)^2}(2x+1)=2.

[题目]椭球面s是椭圆 dfrac ({x)^2}(4)+dfrac ({y)^2}(3)=1 绕x轴旋转而-|||-成,圆锥面s2是过点(4,0)且与椭圆 d

lim _(xarrow 4)dfrac (sqrt {1+2x)-3}(x-4)= (-|||-A dfrac (2)(3) .-|||-B 2-|||-C

设 L 是抛物线=dfrac (1)(4)(x)^2上 点=dfrac (1)(4)(x)^2与 点=dfrac (1)(4)(x)^2 的一段弧则=dfrac

=(e)^2x-|||-2. =(e)^-(x^2)-|||-3. =dfrac ({e)^x}(1+x)-|||-4. =dfrac (sqrt {(x+1)