Question

How do you prove tan(-a) = tan(360°-a) = -tan ?

Answer 1

`-tan(180^o +a)=-tan a`

Explanation:

Perhaps, this is what you expect.

Use tangent is positive in the 1st and third quadrant and negative, in

the 2nd and 4th.

Here, the interpretation depends on the value of `-ain (-pi/2. pi/2)` or `!in (-pi/2, pi/2)`.