Question 403674
These polar coordinates are in the form ({{{r}}},{{{theta}}}), where {{{r}}} is the 
amplitude and {{{theta}}} is the angle in a {{{2*pi}}} radian circle.
{{{theta = -2*pi/3}}}
Note that {{{-pi/3}}} would be {{{-60}}} in degrees
{{{-2*pi/3}}} is {{{-120}}} in degrees. That would put it in the 3rd quadrant,
making  a {{{60}}} degree angle with the horizontal axis.