# Thread: Simple Polar number question...i think...

1. ## Simple Polar number question...i think...

Its quite simple but im not sure of it basically:
Find the argument of
$\displaystyle 1 + itan(\frac{2pi}{3})$

So tan is
$\displaystyle \frac{sin}{cos}$
So i change tan to this and multiply through and get
$\displaystyle cos(\frac{2pi}{3}) + isin(\frac{2pi}{3})$

So i get the answer, the argument is 2pi / 3...seems pretty obvious...except its not...its -1pi / 3

:S, why is this?

2. Originally Posted by AshleyT
Its quite simple but im not sure of it basically:
Find the argument of
$\displaystyle 1 + itan(\frac{2pi}{3})$

So tan is
$\displaystyle \frac{sin}{cos}$
So i change tan to this and multiply through and get
$\displaystyle cos(\frac{2pi}{3}) + isin(\frac{2pi}{3})$

So i get the answer, the argument is 2pi / 3...seems pretty obvious...except its not...its -1pi / 3

:S, why is this?
$\displaystyle \tan \dfrac{2\pi}{3} = -\sqrt{3}$ so that you have $\displaystyle 1-i\sqrt{3}$..

and yeah, $\displaystyle \tan \theta = \dfrac{-\sqrt{3}}{1}$.. and what's arg?

3. Originally Posted by kalagota
$\displaystyle \tan \dfrac{2\pi}{3} = -\sqrt{3}$ so that you have $\displaystyle 1-i\sqrt{3}$..

and yeah, $\displaystyle \tan \theta = \dfrac{-\sqrt{3}}{1}$.. and what's arg?