用洛必达法则求几道题的极限~

1,=lim（x→3.14 /2）cosx/[4sinx(2x-3.14)]
=lim（x→3.14 /2)-sinx/[8sinx+4cosx(2x-3.14)]
=-1/12
2,=lim（x→3.14 /2)(sinxcos3x)/[sin3x cosx]
=lim（x→3.14 /2)(-cos3x/cosx)
=lim（x→3.14 /2)(-3sin3x/sinx)
=3
3,=lim（x→0)(e^x-x-1)/[x(e^x-1)]
=lim（x→0)(e^x-1)/(e^x-1+x*e^x)
=lim（x→0)e^x/[e^x+(x+1)e^x]
=lim（x→0)1/(x+2)
=1/2
4,=lim（x→0+)e^(sinxlnx)
=lim（x→0+)e^[lnx/(1/sinx)]
=lim（x→0+)e^[-sin^2 x/(x*cosx)]
=lim（x→0+)e^(-sinx)-------/*得到这一步是因为lim(x→0)sinx/x=1,且lim（x→0+)1/cosx=1.*/
=lim（x→0+)e^0
=1