Evaluate ` int tan^(-1) x dx`

Explanation

To evaluate the integral \( \int \tan^{-1} x \, dx \), we will use the method of integration by parts. Let's go through the solution step by step.

### Step 1: Set up the integration by parts
We choose:
- \( u = \tan^{-1} x \) (which we will differentiate)
- \( dv = dx \) (which we will integrate)

Using the integration by parts formula:
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