Evaluate: `inttan^3xsec^3x\ dx`

Explanation

To evaluate the integral \( I = \int \tan^3 x \sec^3 x \, dx \), we can follow these steps:

### Step 1: Rewrite the integral
We start with the integral:
\[ I = \int \tan^3 x \sec^3 x \, dx \]
We can express \(\tan^3 x\) in terms of \(\sec^2 x\):
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