Hello skeske1234I think both ways make sense: it just depends what the question is. If it is 'What is the equation of the asymptote?' then the answer is . (Or, in the case of the horizontal asymptote you mention: ).

But if the question is: 'Describe the behaviour of the function as ' then you could say things like 'As '

As to your second question, since a function has at most only one value for each value of , a function cannot crossanyvertical line, whether it's an asymptote or not.

Grandad