1. ## tan²x+4tanx+1=0 help!!

Helppp! tan²x+4tanx+1=0 [0,2pi)
How do you do it? I tried factorising it which isn't possible.
so i used -b+-squareroot of(b^2-4ac)
which got me stuck at (-4 plusminus squareroot of 12 ) / 2
i don't know what to do next.
thanksss

2. Hello, leo037!

$\tan^2\!x+4\tan x+1\:=\:0$

I tried factorising it which isn't possible.

So i used the Quadratic Formula
which got me stuck at: . $\frac{-4 \pm\sqrt{12}}{2} \:=\:-2 \pm\sqrt{3}$

i don't know what to do next.
I used my calculator . . .

$x \;=\;\tan^{-1}(\text{-}2+\sqrt{3}) \:=\:\text{-}\,\frac{\pi}{12}\;\;(\text{-}15^o)$

$x \;=\;\tan^{-1}(\text{-}2-\sqrt{3}) \;=\;\text{-}\,\frac{5\pi}{12}\;\;(\text{-}75^o)$