Is that infinite ?

#lim x-> pi/2 = ((x-pi/2))/((1-sinx)cosx) #

1 Answer
Mar 1, 2017

#-oo#

Explanation:

Calling #y=x-pi/2# we have

# ((x-pi/2))/((1-sinx)cosx) = -y/((1-cos(y))sin(y))#

and also

#lim_( x-> pi/2) ((x-pi/2))/((1-sinx)cosx) =lim_(y->0) -y/((1-cos(y))sin(y))=# #= lim_(y->0)1/(1-cos(y))lim_(y->0)(-y/siny) = oo (-1) = -oo#