Scientific calculator
Trigonometry · logarithms · powers and roots · factorials · pi and e · degrees/radians · keyboard input
科学计算器：常用功能与口径
支持哪些运算。三角函数（sin、cos、tan）与反三角（asin、acos、atan）、自然对数 ln 与常用对数 log、幂运算（x²、x³、任意次方 x 的 y 次方）、平方根与立方根、阶乘、倒数、百分号、常数 π 与 e、括号任意嵌套。还支持隐式乘法：2π、3(4+5)、(1+2)(3+4)、2sin(30) 都按乘号处理。
角度与弧度。键盘上方的 DEG ⇄ RAD 键切换角度单位（状态显示在显示屏右上角）。角度模式下 sin(30) = 0.5；弧度模式下 sin(30) ≈ −0.988。反三角函数按当前模式返回结果：DEG 下 acos(0.5) = 60，RAD 下 = 1.0472。中学数学常用角度模式，微积分常用弧度模式。
常见报错的含义。「无定义域」：负数开平方、asin/acos 自变量超出 [-1,1]、ln(0)、0/0 等实数范围内无解的情况；「结果溢出」：除以 0、10^10000 这类超出双精度浮点范围的结果；「阶乘要求 0~170 的整数」：阶乘只支持非负整数，171 以上直接超出浮点表示范围。这些都是正常的口径提示，不是故障。
百分号与阶乘是后缀运算。50% 表示 50÷100 = 0.5，200×10% = 20；3! = 3×2×1 = 6。百分号不提供取模（余数）运算。输入 = 之后，再按运算符会从上一步结果（Ans）继续算，按数字或函数则开始新算式；Ans 键随时可以引用上一步结果。
关于本页的数据。表达式与结果只在你浏览器里参与计算：页面不发起任何网络请求，不写 localStorage、cookie 或网址参数，刷新即清空。本页采用自研的安全表达式解析器（不用 eval），输入中无法执行任何脚本。
FAQ
Trigonometric functions (sin/cos/tan with inverse asin/acos/atan), logarithms (natural ln, common log), powers and roots (x², x³, x to the y, square root, cube root, absolute value), factorial, reciprocal, percent sign, the constants π and e, arbitrarily nested parentheses and implicit multiplication (2π, 3(4+5) and the like). Everything computes in your browser, no registration needed.
They only differ in the unit of angles: in degree mode sin(30) means 30 degrees and equals 0.5; in radian mode sin(30) means 30 radians, about −0.988. Tap DEG/RAD above the keyboard to switch; the inverse functions (asin/acos/atan) also return results in the current mode. School maths usually uses degrees, university calculus usually radians.
It means the input is outside the range the function accepts: square root of a negative (sqrt(-1)), asin/acos arguments beyond [-1,1] (asin(2)), 0/0 and so on. Division by zero and result overflow (e.g. 10^10000) report 'result overflow'. On a real-number calculator these cases have no real result - the message is normal behaviour, not a fault.
The percent sign is a postfix operator on a number: 50% means 50÷100 = 0.5, and 200×10% equals 20 - the same convention as the percent key on a physical calculator. This page does not offer a modulo (remainder) operator.
No. The expression and the result are used only in your browser's calculation; the page makes no network requests, writes nothing to localStorage, cookies or URL parameters, and refreshing clears everything.