Which of the following could be used as a reference angle for ? 4 O A. O B. 27 4 O C. 37T 4 O D. 4AT 4Which of the following trigonometric ratios is equivalent to sin ? 3 O A. COS 6 O B. COS 3 O C. sin W /y O D. sin 6\fWhich of the following trigonometric ratios is equal to 0? O A. cos IT 0 B. sin 21? O C. cot 317 O D. cos4n Which of the following has the same value as cos 3n? 0 A' sec[3'T] 2 O B we 2 O C [IT] 3111 - 2