limx→∞ cot−1(x+1−x)sec−12x+1x−1x is equal to
1
0
π2
non-existent
limx→∞ cot−1(x+1−x)sec−12x+1x−1x
=limx→∞ cot−11x+1+xsec−12+3x−1x=cot−1(0)sec−1(∞)=π/2π/2=1