Let $[a, b] \subseteq \mathbb{R}$ be a D544: Closed real interval such that
(i) | \begin{equation} a \leq b \end{equation} |
(ii) | $f : [a, b] \to \mathbb{R}$ is a D1760: Riemann integrable real function on $[a, b]$ |
Then
\begin{equation}
\int^b_a f(x) \, d x = \int^{-a}_{-b} f(-x) \, d x
\end{equation}