6.20 求由曲线 _(1)(x)=lim _(xarrow +infty )dfrac (x)(1+{x)^2-(e)^ax} _(2)=dfrac (1)(2)x 及 x=1 所围图形的面积.

令(x)=lim _(xarrow infty )dfrac (1-{e)^-ax}(1+{e)^-ax},则(x)=lim _(xarrow infty )d

lim _(xarrow infty )(x)^2(sqrt (dfrac {1+{x)^2}({x)^2}}-1)= __

求极限 lim _(xarrow +infty )((x+sqrt {1+{x)^2})}^dfrac (1{x)}

求下列极限lim _(xarrow infty )dfrac ({(1+dfrac {1)(x))}^(x^2)}({e)^x}求下列极限

3.求下列函数的极限.-|||-(1) lim _(xarrow infty )x((e)^dfrac (1{x)}-1);-|||-(2) lim _(xar

)求下列极限:-|||-(1) lim _(xarrow 1)dfrac ({x)^2-x+1}({(x-1))^2} =-|||-(3) lim _(xarr

lim _(xarrow +infty )((1+{e)^x)}^dfrac (1{x)};

求lim _(xarrow infty )dfrac ({x)^2-1}(2{x)^2-x-1}-|||-__;求;

lim _(xarrow 0)((dfrac {1+{2)^x}(2))}^dfrac (1{x)}= __

lim _(xarrow infty )(2-dfrac (1)(x)+dfrac (1)({x)^2});;