F-IF.7 and discussion of asymptotes

[SteveG]

F-IF.7e asks for graphing and analysis of exponential and logarithmic functions. While it mentions “end behavior,” it does not use the word asymptote. However, it seems very natural when teaching exponential and logarithmic functions to talk about the equations of the asymptotes. This is especially true when doing transformations (F-BF.3).

However, the only place where “asymptote” appears is in F-IF.7d, which is a plus standard. Some people are interpreting this to mean that there should be no mention of asymptotes at all when teaching to F-IF.7e. That seems a bit extreme to me.
What are your thoughts? I agree that end behavior can be assessed and helpful in conceptual understanding of these functions, but exponential and logarithmic functions have asymptotes — why shouldn’t we use the correct mathematical word when talking about these functions?
Any insight you can offer is greatly appreciated.

[Bill McCallum]

It’s fine to mention asymptotes. The end behavior of an exponential function is that it approaches an asymptote on one side or the other of the $y$-axis. The two terms are not always synonymous, but they are in this case.

[SteveG]

Hey thanks for your quick reply. Some teachers are working on units aligned to CCSS over the summer and your speedy reply helps alot.

[Author]

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