Question

evaluate tan 10 tan 15 tan 75 tan 80

Answer 1

$= \tan(10) \times \tan(80) \times \tan(15) \times \tan(15)$

$= \tan(10) \times \tan(90 - 10) \times \tan(15) \times \tan(90 - 75)$

$= \tan(10) \times \cot(10) \times \tan(15) \times \cot(15)$

$= \tan(10) \times \frac{1}{ \tan(10) } \times \tan( 15) \times \frac{1}{ \tan(15) }$

$= 1 \times 1$

$= 1$

Answer 2

Answer:

here is your answer.

Step-by-step explanation:

tan 10 tan 15 tan 75 tan 80 =

tan (90-80) tan (90-75) tan 75 tan 80

= cot 80 cot 75 tan 75 tan 80

= 1 × 1

= 1