🧮 科学计算器Scientific Calculator

使用说明与常见问题How-to & FAQ

「科学计算器」是什么？What is the Scientific Calculator tool?

功能齐全的在线科学计算器：三角函数（角度/弧度）、对数、幂、开方、阶乘、括号、记忆和历史，支持键盘输入，安全解析不使用 eval。A full scientific calculator: trig (deg/rad), logs, powers, roots, factorial, parentheses, memory and history, with keyboard support and a safe parser (no eval).

如何使用「科学计算器」？How do I use the Scientific Calculator tool?

在「科学计算器」中，在上方填写或选择所需内容，结果会实时显示在下方；所有处理都在浏览器本地完成。In the Scientific Calculator: Fill in or choose the options above and the result appears below instantly; everything runs locally in your browser.

支持省略乘号吗？Can I omit the multiplication sign?

支持在数字、括号后直接接常数、函数或括号的写法，例如 2pi、2(3+4)、(1)(2)、2sin(30)，都会按乘法计算。省略的乘号优先于 × ÷，例如 1/2pi = 1/(2π)；两个数字之间仍需写运算符（如 2 3 会提示错误）。Yes when a number or bracket is followed by a constant, function or bracket, e.g. 2pi, 2(3+4), (1)(2), 2sin(30) are treated as multiplication. An omitted sign binds tighter than × and ÷, so 1/2pi = 1/(2π); two plain numbers still need an operator (2 3 is an error).

为什么 0.1+0.2 显示 0.3？结果精确到几位？Why does 0.1+0.2 show 0.3? How precise are results?

计算机用二进制浮点数计算，0.1+0.2 内部会得到 0.30000000000000004 这类误差。本计算器把结果四舍五入到 14 位有效数字再显示（安全范围内的整数原样显示），因此 0.1+0.2 = 0.3、sin(30°) = 0.5；角度模式下 sin(180°)、cos(90°) 精确为 0，tan(90°) 会提示无定义。Computers use binary floating point, so 0.1+0.2 is internally 0.30000000000000004. Results are rounded to 14 significant digits for display (safe integers are shown exactly), so 0.1+0.2 = 0.3 and sin(30°) = 0.5; in Deg mode sin(180°) and cos(90°) are exactly 0 and tan(90°) reports that it has no value.

它用 eval 吗？安全吗？Does it use eval? Is it safe?

不使用 eval。本计算器自带表达式解析器，只识别数字、运算符和白名单函数，不会执行任意代码。No eval. It has its own expression parser that only understands numbers, operators and a whitelist of functions, so no arbitrary code runs.

「科学计算器」免费吗？需要注册吗？Is the Scientific Calculator free? Do I need an account?

「科学计算器」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 Scientific 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.