2018 · Q55
What is cot 1° cot 23° cot 45° cot 67° cot 89° equal to?
Elementary MathematicsTrigonometry
- A0
- B1
- C1/2
- D1/3
Explanation
Since cot89° = tan1° and cot67° = tan23° (complementary angles) and cot45° = 1, the product is (cot1°·tan1°)(cot23°·tan23°)(1) = 1, option (B).