`int(1-cosx)/(1+cosx)\ dx`

Explanation

To solve the integral \( \int \frac{1 - \cos x}{1 + \cos x} \, dx \), we will follow these steps:

### Step 1: Multiply and Divide by \( 1 - \cos x \)
We start by multiplying and dividing the integrand by \( 1 - \cos x \):

\[ \int \frac{1 - \cos x}{1 + \cos x} \, dx = \int \frac{(1 - \cos x)(1 - \cos x)}{(1 + \cos x)(1 - \cos x)} \, dx \]
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