ASTC
All Stations To China
In A (0-90) All- Sine, Cos, Tan are +
In S (90-180) only Sine is +, everything else is negative-- Easy to Remember cause S for Sine.
In T (180-270) only Tan is +, everything else is negative-- Easy to Remember because T is for Tan.
In C (270-360) only Cos is...