As x approaches or any odd multiple of from the left, y increases; that is, y approaches infinity.Why does it happen? Why is it necessary to keep asymptote?
because you cannot divide by 0
1/0.1 = 10
1/0.01 = 100
1/0.0001 = 1000
as the denominator goes to zero the value becomes unbounded.
Clearly you have not done any reading on this subject. There is a wealth of information online, including videos.