NM, easiiest route to nonsingular

[rbeezer]

A mul;tiple choice question with four choices for theorems/definitons that can be used to determine if a matrix is nonsingular. Important part is that the feedback explains why certain answers are more, or less, easy.

[rbeezer]

Added as commit 98277cf and now visible in the Runestone Academy "playgrouhd" version.

[Tanaquil18]

I think the question would be improved by making the options more of a phrase summarizing the key thing, and then keep the link to the formal theorem or definition in parentheses.

Otherwise, students will likely guess and check without really getting the point of the question.

[Tanaquil18]

Ayla suggested we really do want to have an option that mentions calculating the determinant. Liam and Claire cautioned that it could feel too much like a gotcha question. We all agreed that we want to provide the feedback to students that they should not be talking about determinants in this material, which we used to be able to do when the question was open-ended.

We think we should change the wording of the question slightly to be "what's the easiest way using material from this book so far to recognize if a matrix is nonsingular" and then give calculate the determinant as an option, with feedback of something like "the determinant has not been discussed in this book so far, so that's not what we should be doing."

[rbeezer]

by making the options more of a phrase summarizing the key thing

Yes, I think that would be an improvment. Do you want to make a PR with those changes?

[rbeezer]

really do want to have an option that mentions calculating the determinant

I really do not like the idea of introducing terms that have not yet been defined. Yes, students find this elsewhere. That is nothing new.

"using material from this book so far"

I like that. Then if no option in the multiple choice mentions a determinant, perhaps they'll see why not.