Evaluate $\int_0^3 \lvert x - 1 \rvert\,dx$.

Explanation

1. 01

   Split at $x = 1$: $\int_0^1 (1 - x)\,dx + \int_1^3 (x - 1)\,dx$.

2. 02

   $\frac{1}{2} + 2 = \frac{5}{2}$.