A simple way of understanding how we view graphs is to see where its infinity points end up at. In what quadrant will inf and negative inf be in? That is how we determine the endpoints
Endpoint from degree
All even number degrees will have an endpoint behavior that is horizontal. Either Q1-Q2 or Q3-Q4. All odd number degrees will have endpoint behaviors that are diagonal like: Q3-Q1 or Q4-Q2
Note: We do left to right quadrants so you cannot do Q1-Q3 since that is reading right to left. IT IS ALWAYS Q3-Q1
Endpoint behavior tells us a lot about the Symmetry we will find with the graph, if there is one.