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TeamBasedInquiryLearning / linear-algebra

Materials for running a Team-Based Inquiry Learning linear algebra course
http://linear.tbil.org
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Language about above/below pivots still confusing #350

Closed siwelwerd closed 5 months ago

siwelwerd commented 5 months ago

Some of @jkostiuk's facilitators noted the language in Definition 1.2.6 around zeroes above/below pivots is still confusing--e.g. does "above" mean immediately above, i.e. adjacent?. This was recently modified in #242 , but apparently not sufficiently.

StevenClontz commented 5 months ago

"Every vertical column that includes a pivot has zeros filling every other position." ?

StevenClontz commented 5 months ago

"Every term in a vertical column that includes a pivot, besides the pivot itself, is 0."

siwelwerd commented 5 months ago

I wonder if instead of changing the definition, we could instead change the examples in Activity 1.2.7 and Activity 1.2.8 to highlight this. That is, make sure there is a non-example with zeroes adjacent to the pivot, but a nonzero above or below (but non-adjacent). We'd have to switch them all to $4 \times 4$, but maybe that's okay.

StevenClontz commented 5 months ago

¿Por qué no los dos?

siwelwerd commented 5 months ago

I think the existing language actually says exactly what it should, and in particular I like avoiding the use of row or column there in favor of above/below. I think illustrating via an example will likely be sufficient to clarify this edge case without making the definition more confusing.

jkostiuk commented 5 months ago

I agree completely with the idea of using 4x4 matrices to illustrate and not actually modifying the language