<h2>Hello!</h2>
The answer is:
C. Cosine is negative in Quadrant III
<h2>
Why?</h2>
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°)
Have a nice day!
Using the quadratic formula, the answers could be A B and D
