If x is an angle such that 0 < x < 90°, which of the following statements is not always true?
A. cos(x) > 0
B. cos(-x) > 0
C. cos(x + 90°) < 0
D. cos(2x) < 0
Answer:D
If x is an angle such that 0 < x < 90°, which of the following statements is not always true?
A. cos(x) > 0 B. cos(-x) > 0 C. cos(x + 90°) < 0 D. cos(2x) < 0
Explanation: D