sin 正弦计算器Sine Calculator

使用说明与常见问题How-to & FAQ

「正弦计算器」是什么？What is the Sine Calculator tool?

sin(θ)，可选度/弧度。本地处理。可设置「单位」、「θ」。sin(θ) in degrees or radians. Processed locally. Settings: Unit, θ.

如何使用「正弦计算器」？How do I use the Sine Calculator tool?

在「正弦计算器」中，填写「单位」、「θ」等参数，结果会随输入实时计算并显示在下方。In the Sine Calculator: Fill in "Unit", "θ"; results are recalculated instantly as you type.

计算精度如何？How precise are the results?

度数先对 360° 精确取余再换算，所以很大的角度（如 10¹⁵°）也准确；90° 的整数倍给出精确的 0、1 或 −1，与余弦和单位圆计算器一致。弧度直接用浏览器的 Math.sin（双精度，约 15–16 位有效数字），π/2 的整数倍（10⁹ 以内）也给出精确值。Degrees are first reduced exactly modulo 360°, so very large angles such as 10¹⁵° stay accurate, and whole multiples of 90° give exactly 0, 1 or −1, as on the cosine and unit circle calculators. Radians use the browser's Math.sin (double precision, about 15–16 significant digits), and whole multiples of π/2 up to 10⁹ also give exact values.

能举个计算实例吗？Can you show a worked example?

例如在「正弦计算器」中填 单位 = 度，θ = 30，结果区显示：sin(θ)：0.5For example, entering Unit = Degrees, θ = 30 in the Sine Calculator gives: sin(θ): 0.5

哪些输入会被检查？Which inputs are validated?

「正弦计算器」会检查这些输入——「θ」：所选方式用到时必须填写；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 Sine Calculator checks its inputs — "θ": required when the chosen option uses it; 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?

「正弦计算器」的设置：「单位」可选 度、弧度（默认 度）；「θ」默认 30。每次生成结果都按当前设置处理。Settings in the Sine Calculator — "Unit": Degrees, Radians (default Degrees); "θ" default 30. The result always uses the current settings.

「正弦计算器」免费吗？需要注册吗？Is the Sine Calculator free? Do I need an account?

「正弦计算器」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 Sine 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.