Facts+to+Have+Memorized

Unit 2

A way to memorize your trig functions:

Say you can't remember what the derivatives of your trig functions are during a test, so you nudge your neighbor and say, "Ps**sst**, what's the derivative of sec x?"

sec -> sec <- tan co-functions: csc -> -csc <- cot

So, d/dx[sec x] = secxtanx and d/dx[tan x] = sec 2 x. (You have to look at the set-up backwards for tan.) And, d/dx[csc x] = -cscxcotx and d/dx[cot x] = -csc 2 x.