Mnemonic Device:

• CAST

Explanation: to remember the CAST Rule for trigonometric functions. Go counterclockwise, starting from the bottom right quadrant of graph axes.

• C is the area where the angle is positive for Cosine.
• A is the area where the angle is positive for all trigonometric functions.
• S is the area where the angle is positive for Sine.
• T is the area where the angle is positive for Tangent.

Additional Note: Always measure from the x-axis to the angle line.