Use the All Slappers Take Cash diagram for the sign.
Divide a square into four and label each quadrant like this
SA
TC
Start from the horizontal line between A and C and got anticlockwise.
A - between 0 and 90, all sines, cosines and tans are positive
S - between 90 and 180, only sine is positive
T - between 180 and 270, only tan is positive
C - between 270 and 360, only cosine is positive
This can be verified by considering the graphs of all of these functions