Question

极限 求lim(1-x)tan(πx/2),x趋近于1

Answer 1

=sin(pi*x/2)*(1-x)/cos(pi*x/2)=(1-x)/cos(pi*x/2)
罗比达法则,
=-1/-[sin(pi*x/2)*pi/2]
=1/pi*2=2/pi;