, then the value of cot A is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 2.
| Understanding/Application |
|
(1 - tan A)/(1 + tan A) = (tan3 + tan15 + tan30 + tan75 + tan87)/(tan27 + tan39 + tan51 + tan60 + tan63) (1 - tan A)/(1 + tan A) = (tan3 + tan15 + tan30 + tan(90 -15) + tan(90 - 3))/(tan27 + tan39 + tan(90 -39) + tan60 + tan(90 - 27)) (1 - tan A)/(1 + tan A) = (tan3 + tan15 + tan30 + cot15 + cot3)/(tan27 + tan39 + cot39 + tan60 + cot27) (1 - tan A)/(1 + tan A) = tan30/tan60 (1 - tan A)/(1 + tan A) = 1/3 |
|
3 - 3tan A = 1 + tan A 4 tan A = 2 tan A = 1/2 cot A = 2 |