Question 221254
{{{tan(x) +tan(x+pi/3) +tan(x+2pi/3)=3}}}
<pre><font size = 4 color = "indigo"><b>
Sorry, but that is NOT an identity.  For if 
we substitute {{{x=0}}}:

{{{tan(0) +tan(0+pi/3) +tan(0+2pi/3)=3}}}

{{{tan(0) +tan(pi/3) +tan(2pi/3)=3}}}

And by special angles, {{{tan(0)=0}}}, {{{tan(pi/3)=sqrt(3)}}}, {{{tan(2pi/3)=-sqrt(3)}}}

{{{ 0 +sqrt(3) +(-sqrt(3))=3}}}

{{{0 + sqrt(3) - sqrt(3) = 3}}}

{{{0 = 3}}}

This is false.  Perhaps you copied it wrong.

Edwin</pre>