🔢 区间表示法转换器Interval Notation Calculator

使用说明与常见问题How-to & FAQ

「区间表示法转换器」是什么？What is the Interval Notation Calculator tool?

在不等式和区间表示法之间互相转换：输入如 -2 < x <= 5、x < 1 or x > 4 或 [3, inf)、(1, 3] U [2, 6)，得到区间表示、不等式和集合描述，并自动合并重叠区间。Convert between inequalities and interval notation: enter things like -2 < x <= 5, x < 1 or x > 4, [3, inf) or (1, 3] U [2, 6) to get the interval notation, inequality and set-builder form, with overlapping intervals merged.

如何使用「区间表示法转换器」？How do I use the Interval Notation Calculator tool?

在「区间表示法转换器」中，填写「不等式或区间」等参数，结果会随输入实时计算并显示在下方。In the Interval Notation Calculator: Fill in "Inequality or interval"; results are recalculated instantly as you type.

圆括号和方括号有什么区别？What is the difference between ( and [?

方括号 [ ] 表示包含端点（≤、≥），圆括号 ( ) 表示不包含端点（<、>）。无穷大 ∞ 不是一个数，总是用圆括号。A square bracket includes the endpoint (≤, ≥); a round bracket excludes it (<, >). Infinity is not a number, so it always takes a round bracket.

怎么输入？How do I type the input?

不等式用 x 作变量，可用 <=、>=、≤、≥，多个条件用 and（且）或 or（或）连接；区间可写 inf 或 ∞，并集用 U 或 ∪。Use x as the variable with <, <=, >, >=, ≤ or ≥, joining conditions with and or or. For intervals, write inf or ∞ and join pieces with U or ∪.

计算精度如何？How precise are the results?

「区间表示法转换器」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Interval Notation Calculator uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.

「区间表示法转换器」免费吗？需要注册吗？Is the Interval Notation Calculator free? Do I need an account?

「区间表示法转换器」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Interval Notation Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.