Find the value of cot5° . cot15° . cot25° . cot35° . cot45° . cot55° . cot65°. cot75° . cot85° .

6 -1 1 0

1

⇒ cot5° . cot15° . cot25° . cot35° . cot45° . cot55° . cot65°. cot75° . cot85° Here, ⇒ (cot A . cot B = 1, when A + B = 90°) So, ⇒ (cot5° . cot85°) . (cot15° . cot75°) . (cot25° . cot65°) . (cot35° . cot55°) . cot45° = 1 × 1 × 1 × 1 × 1 = 1