# Thread: Hyperbolic Graph Problem

1. ## Hyperbolic Graph Problem

Hi,
please find attached the problem and the short and sweet Answer.
I can't understand the last step of the answer.

2. Originally Posted by trojsi
Hi,
please find attached the problem and the short and sweet Answer.
I can't understand the last step of the answer.
$
-2e^k + 4e^{-k} = -2
$

Moving everything to the left

$
-2e^k + 2 + 4e^{-k} = 0
$

Factorising $-2e^{-k}$

$
-2e^{-k}(e^{2k} - e^k -2) = 0
$

Divide both sides by $-2e^{-k}$

$
e^{2k} - e^k -2 = 0
$

3. tnx a lot so simple.. yet so much to assimilate

thanks again

Brandon