1.用洛必达法则求下列各极限:-|||-(1) lim _(xarrow 0)dfrac (ln (1+x))(x)-|||-(3) lim _(xarrow a)dfrac (cos x-cos a)(x-a);-|||-(5) lim _(xarrow dfrac {pi )(2)}dfrac (ln sin x)({(pi -2x))^2};-|||-(7) lim _(xarrow 0)+dfrac (ln tan 3x)(ln tan 4x);-|||-(9) lim _(xarrow +infty )dfrac (ln (1+dfrac {2)(x))}(arctan x)-|||-(11)lim xcot 3x;-|||-(13) lim _(xarrow 1)(dfrac (2)({x)^2-1}-dfrac (1)(x-1))-|||-1515) limx^(100°;;-|||-(2) lim _(xarrow 0)dfrac ({e)^x-(e)^-x}(sin x)-|||-(4) lim _(xarrow 0)dfrac (sin ax)(tan bx)(bneq 0)-|||-(6) lim _(xarrow a)dfrac ({x)^5-(a)^5}({x)^3-(a)^3}-|||-(8) lim _(xarrow dfrac {pi )(2)}dfrac (tan x)(tan 5x);-|||-(10) lim _(xarrow 0)dfrac (ln (1+{x)^2)}(sec x-cos x)-|||-(12) lim _(xarrow 0)(x)^2(e)^dfrac (1{{x)^2}} =-|||-(14) lim _(xarrow infty )((1+dfrac {3)(x))}^x =-|||-(16) lim _(xarrow 0+{(dfrac {1)(x))}^sin x}