In Case You Haven't Yet Memorized the Trig Function Derivatives

The way I remember them is:

1. sine and cosine are mutual derivatives (almost; see rule 2)
2. every co- function has a minus sign in its derivative
3. when working with secant or tangent, you get the derivative of the one by multiplying the other by secant
4. when working with cosecant or cotangent, you get the derivative of one by multiplying the other by cosecant (very similar to rule 3)

If anyone else has good, easy to remember rules, or improvements on these, please comment.