limx→π2 ecos x−1cos x
Let x=π2+h ⇒x−π2=h
as x →π2,h→0
=limx→π2 e−sinh−1−sin h
limx→π2ecos(π2+4)−1cos(π2+4)
=1
limx→π22−cosx−1x(x−π2)