Hello friends, I know, and there is this formula for the sum of sines:

$\displaystyle sin(\alpha) + sin(\beta) = 2sin( \displaystyle\frac{\alpha + \beta}{2} ) cos( \displaystyle\frac{\alpha - \beta}{2} )$

and there is one for the sum of cosines,

I wonder if there is a similar to this:

$\displaystyle tan(\alpha) + tan(\beta)$

greetings