Evaluate: `intx^3logx\ dx`

Explanation

To evaluate the integral \( I = \int x^3 \log x \, dx \), we will use the method of integration by parts. The formula for integration by parts is given by:

\[ \int u \, dv = uv - \int v \, du \]

### Step 1: Choose \( u \) and \( dv \)

...