If you have studied complex function, you will know that a straight line is a circle with infinite radius. This sentence is correct and can be strictly proved.

I want to ask: what is the concept of limit in your mind?

For example, Lin [(n→∞), (1/n)]=0, because 1/n itself is not equal to 0, so according to what you said, this equation is not valid, is it?

I don't want to give you the concept of limit, because you know.

So do you really understand what it means?