Extraneous Solutions – Part 1 of 3?
Disclaimer Within my small inner circle of math teachers, the mystery of extraneous solutions seems to be the issue of the year. I have so much to say on this topic (algebraic, logical, pedagogical,...
View ArticleExtraneous Solutions – Part 2 of 3
Solving an Equation as a Sequence of Equation Replacement Operations Part 1 was so long because I wanted to be extremely thorough and to present things to an audience that perhaps hadn’t thought much...
View ArticleThe Product Rule
At some point in every calculus class, we must discover and prove the product rule for derivatives. How a calculus teacher chooses to do this probably says a lot about their pedagogy and educational...
View ArticleDerivatives of Trigonometric Functions
First, let’s present the standard approach. This is from the calculus textbook I teach out of. This was, as far as I was concerned, the only possible proof. The pedagogical flexibility lay entirely in...
View ArticleGeometric Proofs of Trigonometric Identities
Sparked by a conversation this past weekend about the usefulness of the half-angle identities, I constructed geometric proofs for and . Since I’ve never seen these anywhere before, I thought I’d share....
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