4.已知曲线 y=f(x) 在点(0,0)处的切线过点(1,2),则-|||-lim _(xarrow 0)([ cos x+{int )_(0)^xf(t)dt] }^dfrac (1{{x)^2}}= __

已知曲线 y=f(x) 在点(0,1)处的切线与曲线 =ln x 相切,则 lim _(xarrow 0)dfrac (f(sin x)-1)(x+sin x)

设f`(x)连续, (0)=0, (0)=2, 极限 lim _(xarrow 0)dfrac ({int )_(0)^xln cos (x-t)dt}(sqr

[题目]已知函数f(x,y)在点(0,0)的某个邻域内连-|||-续,且 lim _(xarrow 0)dfrac (f(x,y)-xy)({({x)^2+(y

已知函数f(x,y)在点(0,0)的某个邻域内连续，且lim_(x to 0 cdot y to 0) (f(x,y))/(1-cos(x^2)+y^(2))=

lim _(xarrow 0)dfrac ({int )_(x)^0((e)^t+(e)^-t-2)dt}(1-cos x) ()-|||-__=（）=（）A.

[题目]已知f(x)在 x=0 的某个邻域内连续,且-|||-(0)=0, lim _(xarrow 0)dfrac (f(x))(1-cos x)=2, 则在

(1) lim _(xarrow 0)dfrac ({({int )_(0)^x(e)^(t^2)dt)}^2}({int )_(0)^xt(e)^2(t^2)

求极限lim _(xarrow 0)dfrac ({int )_(0)^x(1-cos t)dt}({x)^3}= (ost)dt/=()。求极限。

已知 lim _(xarrow 0)([ 1+x+dfrac {f(x))(x)] }^dfrac (1{x)}=(e)^3, 则 lim _(xarrow 0

4.函数f(x,y)=x^2+xy+y^2在点(0,0)处（）.A. 有极大值;B. 有极小值;C. 无极值;D. 点(0,0)不是驻点.