∿ 三角函数Trigonometric Functions Calculator
sin / cos / tan（度或弧度）。本地处理。可设置「角度 / 弧度值」、「单位」。sin / cos / tan in degrees or radians. Processed locally. Settings: Angle value, Unit.
使用说明与常见问题How-to & FAQ
「三角函数」是什么？What is the Trigonometric Functions Calculator tool?
sin / cos / tan（度或弧度）。本地处理。可设置「角度 / 弧度值」、「单位」。sin / cos / tan in degrees or radians. Processed locally. Settings: Angle value, Unit.
如何使用「三角函数」？How do I use the Trigonometric Functions Calculator tool?
在「三角函数」中，填写「角度 / 弧度值」、「单位」等参数，结果会随输入实时计算并显示在下方。In the Trigonometric Functions Calculator: Fill in "Angle value", "Unit"; results are recalculated instantly as you type.
能算反三角函数吗？Does it do inverse trig functions?
不能，本页只算正向的 sin、cos、tan，角度可用度或弧度。已知函数值求角度（arcsin、arccos、arctan）需要用反三角函数工具。No, only the forward functions sin, cos and tan, with the angle in degrees or radians. To find an angle from a value (arcsin, arccos, arctan), use an inverse trig tool.
能举个计算实例吗？Can you show a worked example?
例如在「三角函数」中填 角度 / 弧度值 = 30，单位 = 度，结果区显示：sin：0.5；cos：0.8660254038；tan：0.5773502692For example, entering Angle value = 30, Unit = Degrees in the Trigonometric Functions Calculator gives: sin: 0.5; cos: 0.8660254038; tan: 0.5773502692
哪些输入会被检查？Which inputs are validated?
「三角函数」会检查这些输入——「角度 / 弧度值」：必须填写，须不小于 -1,000,000,000且不大于 1,000,000,000；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Trigonometric Functions Calculator checks its inputs — "Angle value": required, must be at least -1,000,000,000 and at most 1,000,000,000; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.
有哪些选项可以调整？What options can I adjust?
「三角函数」的设置：「角度 / 弧度值」默认 30；「单位」可选 度、弧度（默认 度）。每次生成结果都按当前设置处理。Settings in the Trigonometric Functions Calculator — "Angle value" default 30; "Unit": Degrees, Radians (default Degrees). The result always uses the current settings.
计算精度如何？How precise are the results?
「三角函数」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 Trigonometric Functions Calculator uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.
「三角函数」免费吗？需要注册吗？Is the Trigonometric Functions Calculator free? Do I need an account?
「三角函数」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 Trigonometric Functions 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.