To evaluate the integral \( I = \int \frac{dx}{x^2 \sqrt{1+x^2}} \), we will follow these steps:
### Step 1: Rewrite the Integral
We start by rewriting the integral:
\[
I = \int \frac{dx}{x^2 \sqrt{1+x^2}}
\]
We can factor out \( x^2 \) from the square root in the denominator:
...
