Hello!
The answer is:
C. Cosine is negative in Quadrant III
Why?
Let's discard each given option in order to find the correct:
A. Tangent is negative in Quadrant I: It's false, all functions are positive in Quadrant I (0° to 90°).
B. Sine is negative in Quadrant II: It's false, sine is negative in positive in Quadrant II. Sine function is always positive coming from 90° to 180°.
C. Cosine is negative in Quadrant III. It's true, cosine and sine functions are negative in Quadrant III (180° to 270°), meaning that only tangent and cotangent functions will be positive in Quadrant III.
D. Sine is positive in Quadrant IV: It's false, sine is negative in Quadrant IV. Only cosine and secant functions are positive in Quadrant IV (270° to 360°)
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