Part 4/6:
- In the fourth quadrant (between 270 and 360 degrees), cosine is positive, but sine and tangent are negative.
Understanding these sign changes is crucial when evaluating trigonometric functions for any angle.
The All Students Take Calculus Rule
A mnemonic to remember the signs of trigonometric functions in each quadrant is "All Students Take Calculus." In this phrase:
All - Sine, Cosine, and Tangent are all positive in the first quadrant.
Sine - only sine is positive in the second quadrant.
Tangent - only tangent is positive in the third quadrant.
Cosine - only cosine is positive in the fourth quadrant.