Getting Shirty

[stoutfellow]

Today, between classes, I stopped off for a restroom break. As I entered, a couple of students came out. One of them had a t-shirt, with the words (and mathematical symbols) "I'm :square root of one-plus-tan-squared-C: and I know it!" I took a moment to process it, then turned and called after him: "That's a *terrible* t-shirt!" He turned back, grinning, and said "Did you get it?" "Yes, I got it!". I turned back toward the restroom and he went on his way, undoubtedly pleased with himself.

Comments

[ndrosen]

I’m sorry, I must be losing either my math or my wits. What is C, that one can know what its tangent is? And tan squared would presumably be a positive real number, so if you add that to one and take the square root, what’s weird or boastful about the result?

[stoutfellow]

One of the variants of the Pythagorean identity: 1 plus the square of the tangent function is the square of the secant function. "Secant" is usually abbreviated "sec", pronounced "seek" or "seck".

[ndrosen]

OK, now I get it. Thank you.