Question

if tan5°=a, find value of tan80° in terms of a.

Answer 1

Answer:

(1-a^2)/2a

Step-by-step explanation:

Tan80°= Cot10°

Tan5° = a

Tan10° = Tan(2×5°)

= (2Tan5°) /1- Tan^2(5°)

=2a/1-a^2

Implies, Cot10° = (1-a^2)/2a

Hence, Tan80° = (1-a^2)/2a

Answer 2

Step-by-step explanation:

given tan 5=a

tan 80=?

tan 80=tan(90-10)

=cot 10

=1/tan10

=2tan(5)

=2a