Tunjukkan kebenaran identitas trigonometri 1+cotanx/1-cotanx = 1+tanx/tanx-1 !

[tex]$\begin{align}\frac{1+\cot x}{1-\cot x}&=\frac{1+\dfrac1{\tan x}}{1-\dfrac1{\tan x}}\\&=\frac{~~\dfrac{\tan x+1}{\tan x}~~}{\dfrac{\tan x-1}{\tan x}}&&\to\text{coret penyebut} \tan x\\&=\boxed{\frac{\tan x+1}{\tan x-1}}\ \ \bold{(terbukti)} \end[/tex]