> For the complete documentation index, see [llms.txt](https://yingshaoxo.gitbook.io/university-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yingshaoxo.gitbook.io/university-notes/high-level-math/integration/definite-integral.md).

# Definite integral

![](https://2889346953-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Le4Kw7maZEabKFjsC7z%2F-Lf5hWWAPXrS6pkg310z%2F-Lf5hmoEofEDISJbPRaP%2Fdefinite_integral.png?generation=1558112056145719\&alt=media)

$$\sqrt{2}$$ = The square root of 2

$$x^2$$ = x squared

$$
Trapezoid(梯形面积公式) = \frac{base\_{up} + base\_{down}}{2} \times height
$$