Question

How do you prove tan(180°+a) = tan(a)?

Answer 1

This result is significant in disclosing that tan function is periodic with period `pi=180^o`.Use `tan(a+b)=(tana+tanb)/(1-tana tanb), b=180^o and tan 180^o=0`.

Explanation:

Note that the period of sint and cost is #2pi=3680^o and, for tan t, it

is `pi=180^0`