Appropriate theme for a math teacher, the six TRIG functions hidden within phrases — in order! Not that there's an absolute right ...
read moreAppropriate theme for a math teacher, the six TRIG functions hidden within phrases — in order! Not that there's an absolute right order in which to present the six, but SIN COS TAN, COT (cotangent) SEC (secant) CSC (cosecant) is how math books go over them.

(CSC is the inverse of SIN, SEC inverse of COS, COT inverse of TAN, in case you're interested. I know you're probably not, but I am. So there.)
On one hand, there's something impressive about packing in the seven themers. In order! I particularly like HIT A NERVE hiding TAN; great phrase. And there's something awesome about SEC hidden inside MORSE CODE. Feels like the plot of a Dan Brown book.
On the other, so many constraints producing so many compromises in the grid hit a nerve for me. I personally wouldn't allow THAN I (partial) crossing LENAS (plural name). Then you get ANS, LTR, DIAS, the oddly related seeming ECCE ESSO OSS, RETOW … that's not good at all.
And LEFT RIGHT … I get that you need a middle themer hiding TRIG. But LEFT RIGHT was last used in the Maleskan era. Is it a valid phrase? Dunno. At the very least, I had enough hesitations that I would have much preferred something different. JUST RIGHT would have been a lot better to me, but that J would have stressed the grid even more. PATENT RIGHT is better too, but it's more common in the plural.
Maybe even leaving out TRIG would have been better. SIN COS TAN tells the story pretty well without TRIG, anyway.
I did love the clue for TACO STAND. [Shell station?] hinting at the Shell gas stations, misdirecting from TACO shells = brilliant.
And that clue for MORSE CODE! I fell into Pete's trap with both feet. Part of me still wonders what that ellipsis is leading to!
The math-lover in me enjoyed seeing the TRIG functions in proper order. The crossword-lover in me had problems with the execution.