Differentiate w.r.t x
`(1-cos x)//(1+ cos x)`

Explanation

To differentiate the function \( y = \frac{1 - \cos x}{1 + \cos x} \) with respect to \( x \), we will use the quotient rule. The quotient rule states that if you have a function \( y = \frac{u}{v} \), then the derivative \( \frac{dy}{dx} \) is given by:

\[ \frac{dy}{dx} = \frac{v \frac{du}{dx} - u \frac{dv}{dx}}{v^2} \]

where \( u = 1 - \cos x \) and \( v = 1 + \cos x \).

...