Area Between a Curve and the x-Axis
If $$f(x)$$ changes sign at roots:
$$x_1,x_2,\ldots,x_n$$
then the total area is:
$$A=\sum_{i=0}^{n}\left|\int_{x_i}^{x_{i+1}}f(x)\,dx\right|$$
Usage
- Used to calculate total geometric area when the curve crosses the $$x$$-axis multiple times.