Author Archives: Santo D'Agostino

About Santo D'Agostino

I have taught mathematics and physics since the mid 1980s. I have also been a textbook writer/editor since then. Currently I am working independently on a number of writing and education projects while teaching physics at my local university. I love math and physics, and love teaching and writing about them. My blog also discusses education, science, environment, etc. Further resources, and online tutoring, can be found at my other site

How does the value of an inverse cosine function change when the unit of its argument changes?

How does the value of differ from ?   This is an interesting question, especially because the question of units in trigonometric and inverse trigonometric functions is rarely discussed in mathematics textbooks.   If you’re interested, think this problem through … Continue reading

Posted in Mathematics | Tagged , , , | 2 Comments

Why do Airplanes Fly?

In many physics textbooks, the explanation for lift on a flying airplane is that the top of a plane’s wing is longer than the bottom, and so air must travel faster across the top than the bottom, and therefore the … Continue reading

Posted in Physics | Tagged , , , , | 4 Comments

New Online Tutoring Site: QED Infinity

Well, it’s been a long time since I’ve posted here. I’ve been involved in a number of writing and education projects, and one of them has now surfaced: My new online tutoring site, QED Infinity. The main purpose of QED … Continue reading

Posted in QED Infinity | Tagged , , | 6 Comments

“Religious Right’s Rejection of Science is Baffling,” by David Suzuki

Religion at its best helps humans to form loving, supportive communities, and helps each person to connect to something larger than himself. Religion at its worst separates groups into the “us” that have the Truth, and the “them” that live … Continue reading

Posted in Environment, Society | Tagged , , , , , , | 8 Comments

The Day Niagara Falls Ran Dry

If you’ve had the pleasure of standing right next to the roaring water falling over the precipice at Niagara Falls (and for me, it’s the sound that’s most impressive), then it’s hard to believe that the flow once naturally stopped … Continue reading

Posted in Nature | Tagged , , | 3 Comments

“A Lesson in Teaching to the Test, From E.B. White,” by Anne Stone and Jeff Nichols

Anne Stone and Jeff Nichols beautifully make the case against standardized testing at the New York Times SchoolBook blog (hat-tip to Susan Ohanian). Here is an excerpt: In light of current controversies around testing and teacher evaluation, let’s do a … Continue reading

Posted in Education | Tagged , , , , | 19 Comments

“Student Learning Can Only Be Described, Not Measured,” by Rog Lucido

Rog Lucido has written an interesting article against standardized testing, and suggesting better alternatives. (Hat-tip to Susan Ohanian.) He argues that the numerical aggregation of final test scores is not valid and therefore not meaningful, and that subjective assessments together … Continue reading

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