Question

用洛必达法则求 lim X趋近于π/2 tan3x/tan5x

Answer 1

7、原式=limx→0 [e^x+e^(-x)-2]/2x
=limx→0 [e^x-e^(-x)]/2
=(1-1)/2=0；
8、limx→0 [x-e^x+1]/[x(e^x-1)]
=limx→0 (1-e^x)/[(e^x-1)+x*e^x]
=limx→0 -e^x/(e^x+e^x+x*e^x)
=-1/(1+1+0)
=-1/2.