➗ 数学工具Math （第 3 页）(page 3)
参考角计算器（度、弧度、象限、同终边角）Reference Angle Calculator (Degrees, Radians, Quadrant, Coterminal Angles)
把任意角（可为负数或大于 360°）化到 0–90° 的参考角，支持度、弧度和 π 弧度输入。同时给出 0–360° 内的同终边角、所在象限或坐标轴，以及 sin、cos、tan 在该象限的符号。本地处理。Reduces any angle (negative or above 360°) to its reference angle between 0 and 90°, with degrees, radians or multiples of π as input. Also gives the coterminal angle in 0–360°, the quadrant or axis, and the signs of sin, cos and tan there. Processed locally.
黎曼和计算器（左/右/中点/梯形，任意函数）Riemann Sum Calculator (Left, Right, Midpoint, Trapezoid for Any Function)
输入函数 f(x)（如 x^2、sin(x)、exp(-x)），区间 [a, b] 和分割数 n，计算左端点、右端点、中点黎曼和以及梯形法则的近似值，并与辛普森法的高精度积分对比误差，列出每个子区间的取样点。也保留常数函数模式。本地处理。Enter a function f(x) (such as x^2, sin(x) or exp(-x)), an interval [a, b] and the number of subintervals n to get the left, right and midpoint Riemann sums and the trapezoid rule, compared against a high-accuracy Simpson integral, with the sample points listed for each subinterval. The constant-function mode is kept. Processed locally.
SAS 三角形计算器（两边夹角求全部）SAS Triangle Calculator (Two Sides and the Included Angle)
已知两边 a、b 及其夹角 C，用余弦定理求第三边 c，用正弦/余弦定理求另外两个角 A、B，并给出面积、周长、三条高、外接圆和内切圆半径，以及三角形类型（锐角/直角/钝角）。本地处理。Given two sides a and b and the included angle C, finds the third side c by the law of cosines and the other angles A and B, plus the area, perimeter, all three heights, circumradius, inradius and the triangle type (acute, right or obtuse). Processed locally.
学期成绩计算器（加权平均、百分比权重、期末需考多少分）Semester Grade Calculator (Weighted Average, Percentage Weights, Final Exam Needed)
两种用法：输入各项成绩和权重（可以是学分、次数或百分比）求加权平均分并换算等级；或者输入目前的学期成绩、期末考试所占比例和目标总评，算出期末考试至少需要考多少分。本地处理。Two uses: enter each grade with its weight (credits, counts or percentages) for the weighted average and letter grade; or enter your current grade, the weight of the final exam and the grade you want, to see the minimum score you need on the final. Processed locally.
相似三角形计算器（比例因子、求未知边、面积比）Similar Triangles Calculator (Scale Factor, Missing Sides, Area Ratio)
已知一对对应边 a 和 a′，求比例因子 k = a′/a，再求另一条边的对应边；或输入两个三角形的三条边，检验是否相似（SSS），并给出比例因子、周长比和面积比（k²）。本地处理。From one pair of corresponding sides a and a′ get the scale factor k = a′/a and the matching side for another side; or enter all three sides of both triangles to test similarity (SSS) and get the scale factor, perimeter ratio and area ratio (k²). Processed locally.
根式化简计算器（平方根、立方根、n 次根、系数）Simplify Radicals Calculator (Square, Cube and nth Roots, With a Coefficient)
把 k·ⁿ√x 化成最简根式 a·ⁿ√b（b 不含 n 次方因数），支持平方根、立方根和任意 n 次根，可带系数，负数的奇次根会保留负号。同时给出质因数分解、提出的因数和小数值。本地处理。Simplifies k·ⁿ√x to simplest radical form a·ⁿ√b (b has no nth-power factor) for square, cube or any nth roots, with an optional coefficient; odd roots of negative numbers keep the minus sign. Also shows the prime factorisation, the factor taken out and the decimal value. Processed locally.
坡度计算器（百分比、角度、比例 1:n 互换）Slope Calculator (Percent, Degrees and 1:n Ratio)
由升高和水平距离求坡度百分比、角度和 1:n 比例，或者从已知百分比、角度、比例中任意一个换算出其余，并给出斜面长度。常用于道路、坡道（无障碍坡道 1:12 ≈ 8.33 %）、屋顶和排水坡度。本地处理。From rise and run get slope as a percentage, an angle and a 1:n ratio, or convert from any one of percent, degrees or ratio to the others, with the slope length. Useful for roads, ramps (accessible ramps 1:12 ≈ 8.33 %), roofs and drainage. Processed locally.
子集计算器（C(n,k) 计数、列出子集、真子集、至多/至少 k 个）Subset Calculator (Count C(n,k), List Subsets, Proper Subsets, At Most or At Least k)
计算从 n 个元素中取 k 个的子集数 C(n, k)（大整数精确值），以及全部子集数 2ⁿ、真子集数 2ⁿ − 1、至多 k 个和至少 k 个元素的子集数；输入具体元素时列出所有 k 元子集，或检验一个集合是否是另一个集合的子集。本地处理。Counts the subsets with k of n elements, C(n, k), exactly with big integers, plus all subsets 2ⁿ, proper subsets 2ⁿ − 1, and subsets with at most or at least k elements; with actual elements it lists every k-element subset, or tests whether one set is a subset of another. Processed locally.
代入法解方程组计算器（二元/三元一次，含步骤）Substitution Method Calculator (2×2 and 3×3 Linear Systems, With Steps)
用代入法解二元一次方程组 a₁x + b₁y = c₁、a₂x + b₂y = c₂，并写出每一步：从一个方程解出一个变量、代入另一个方程、求值、回代。判断无解（平行）或无穷多解（重合），并可切换到三元一次方程组。本地处理。Solves a₁x + b₁y = c₁ and a₂x + b₂y = c₂ by substitution, showing each step: isolate a variable in one equation, substitute it into the other, solve, and back-substitute. Detects no solution (parallel lines) or infinitely many (the same line), and also handles 3×3 systems. Processed locally.
正切计算器（tan、cot、反正切，度/弧度）Tangent Calculator (tan, cot, Arctangent, Degrees or Radians)
计算角的正切 tan θ 和余切 cot θ，支持度和弧度；常见角会给出精确值（如 tan 30° = √3/3）。也可以反过来由正切值求角度 arctan，或由直角三角形的对边和邻边求 tan 和角度。本地处理。Calculates tan θ and cot θ in degrees or radians, with exact values for common angles (tan 30° = √3/3). Also works backwards with arctan from a tangent value, or from the opposite and adjacent sides of a right triangle. Processed locally.
顶点式计算器（一般式 ↔ 顶点式，顶点、对称轴、根）Vertex Form Calculator (Standard ↔ Vertex Form, Vertex, Axis, Roots)
把 y = ax² + bx + c 化成顶点式 y = a(x − h)² + k（整数系数时给出精确分数），或由顶点式展开成一般式；同时给出顶点、对称轴、开口方向、最值、与 x 轴的交点和 y 截距。本地处理。Turn y = ax² + bx + c into vertex form y = a(x − h)² + k (exact fractions for integer coefficients), or expand vertex form back to standard form. Also shows the vertex, axis of symmetry, direction of opening, minimum or maximum, x-intercepts and y-intercept. Processed locally.
三棱锥体积计算器（底面积、三边、正四面体）Triangular Pyramid Volume Calculator (Base Area, Three Sides, Regular Tetrahedron)
三棱锥（四面体）体积 V = 底面积 × 高 ÷ 3。底面可直接填面积、填三角形底和高、填三边（海伦公式），也可按正四面体只填棱长（V = a³ ÷ (6√2)）。本地处理。Triangular pyramid (tetrahedron) volume V = base area × height ÷ 3. Give the base as an area, as a triangle base and height, or as three sides (Heron's formula), or choose a regular tetrahedron and enter only the edge (V = a³ ÷ (6√2)). Processed locally.
分数化简计算器（最简分数、带分数、循环小数）Simplify Fractions Calculator (Lowest Terms, Mixed Number, Repeating Decimal)
把分数化成最简分数：给出最大公约数、约分步骤、带分数、小数（循环小数用括号标出循环节）和百分数，分子分母可为负数。本地处理。Reduce a fraction to lowest terms with the greatest common divisor, the reduction step, the mixed number, the decimal (repeating digits shown in brackets) and the percentage. Negative numerators and denominators are allowed. Processed locally.
分数加减计算器（带分数、通分步骤、最简结果）Adding and Subtracting Fractions Calculator (Mixed Numbers, Common Denominator Steps)
计算两个分数或带分数的和与差：先化成假分数，用最小公倍数通分，给出每一步、最简结果、带分数和小数。整数部分可留空，分子可为负数。本地处理。Add or subtract two fractions or mixed numbers: convert to improper fractions, use the least common denominator, and see every step, the result in lowest terms, as a mixed number and as a decimal. Whole parts may be blank; numerators may be negative. Processed locally.
圆锥计算器（体积、侧面积、表面积、母线、由体积反求高）Cone Calculator (Volume, Lateral and Total Surface Area, Slant Height, Height from Volume)
圆锥的体积 V = πr²h/3、母线 l = √(r² + h²)、侧面积 πrl、表面积 πr(r + l) 和顶角。已知量可以是半径和高、半径和母线，或半径和体积（反求高）。本地处理。Cone volume V = πr²h/3, slant height l = √(r² + h²), lateral area πrl, total surface area πr(r + l) and apex angle. Start from radius and height, radius and slant height, or radius and volume (solves for the height). Processed locally.
圆台计算器（体积、母线、侧面积、表面积、容积升数）Conical Frustum Calculator (Volume, Slant Height, Lateral and Surface Area, Capacity in Litres)
圆台（截头圆锥）体积 V = πh(R² + Rr + r²)/3，母线 s = √((R − r)² + h²)，侧面积 π(R + r)s，表面积再加两个底面；以厘米为单位时还给出容积（升），适合水桶、花盆等。本地处理。Conical frustum (truncated cone) volume V = πh(R² + Rr + r²)/3, slant height s = √((R − r)² + h²), lateral area π(R + r)s and total surface area including both bases; in centimetres it also gives the capacity in litres, handy for buckets and planters. Processed locally.
平面两点距离计算器（精确根式、中点、斜率、方位角）2D Distance Calculator (Exact Radical, Midpoint, Slope, Bearing)
计算平面上两点 (x₁, y₁)、(x₂, y₂) 的距离 d = √((x₂ − x₁)² + (y₂ − y₁)²)，整数坐标时给出化简根式（如 2√5），同时给出 Δx、Δy、中点、斜率和方向角。本地处理。Distance between two points (x₁, y₁) and (x₂, y₂) in the plane, d = √((x₂ − x₁)² + (y₂ − y₁)²), as a simplified radical for integer coordinates (e.g. 2√5), plus Δx, Δy, midpoint, slope and direction angle. Processed locally.
五次方根计算器（实根、是否为完全五次方、全部 5 个复数根）Fifth Root Calculator (Real Root, Perfect Fifth Power Check, All 5 Complex Roots)
求 x 的五次方根：负数也有实数五次方根（如 ⁵√−32 = −2）；判断是否为完全五次方，并列出 5 个复数根 r^(1/5)·(cos θ + i sin θ)。本地处理。Find the fifth root of x: negative numbers have a real fifth root too (⁵√−32 = −2). Checks for a perfect fifth power and lists all 5 complex roots r^(1/5)·(cos θ + i sin θ). Processed locally.
最小公倍数计算器（多个数、质因数分解、最大公约数）LCM Calculator (Least Common Multiple of Several Numbers, Prime Factorisation, GCD)
求 2–20 个正整数的最小公倍数（LCM）和最大公约数（GCD），列出每个数的质因数分解，并说明 LCM 取每个质因数的最高次幂。用空格、换行或逗号分隔（如 12 18 30）。大数用精确整数计算。本地处理。Least common multiple (LCM) and greatest common divisor (GCD) of 2–20 positive integers, with the prime factorisation of each and how the LCM takes the highest power of every prime. Separate numbers with spaces, line breaks or commas (e.g. 12 18 30). Exact integer arithmetic for large results. Processed locally.
竖式减法计算器（任意位数、小数、逐位借位步骤）Long Subtraction Calculator (Any Number of Digits, Decimals, Borrowing Step by Step)
用竖式计算两个数相减：支持任意位数的整数和小数（精确计算，不经过浮点），显示竖式排列、每一位的借位，以及结果为负时的处理。本地处理。Long (column) subtraction of two numbers: integers and decimals of any length, computed exactly without floating point. Shows the column layout, each borrow and how a negative result is handled. Processed locally.
数位计算器（每一位的数位名称、位值、展开式，含小数）Place Value Calculator (Place Names, Digit Values, Expanded Form, Decimals)
列出一个数每一位数字所在的数位（个、十、百、千、万…以及十分位、百分位…），每位的位值和展开式；支持最多 30 位整数和 15 位小数，可带负号。本地处理。Shows the place of every digit (ones, tens, hundreds, thousands… and tenths, hundredths…), the value of each digit and the expanded form, for up to 30 integer digits and 15 decimal places, with an optional minus sign. Processed locally.
长方体计算器（体积、表面积、体对角线、面对角线）Rectangular Prism Calculator (Volume, Surface Area, Space and Face Diagonals)
由长、宽、高求长方体（立方体为特例）的体积 V = lwh、表面积 2(lw + lh + wh)、体对角线 √(l2 + w2 + h2) 和三个面的对角线；以厘米为单位时还给出容积升数。本地处理。From length, width and height get the volume V = lwh, surface area 2(lw + lh + wh), space diagonal √(l2 + w2 + h2) and the three face diagonals of a rectangular prism (a cube is a special case); in centimetres it also gives the capacity in litres. Processed locally.
菱形Rhombus Calculator
由对角线：面积 = d1d2/2，边 = √((d1/2)2+(d2/2)2)。本地处理。可设置「对角线 1」、「对角线 2」。From diagonals: area = d1d2/2; side = √((d1/2)2+(d2/2)2). Processed locally. Settings: Diagonal 1, Diagonal 2.
求和Sum Calculator
对一列数字求和（空格/逗号/换行分隔）。本地处理。Sum a list of numbers (space/comma/newline separated). Processed locally.
三棱柱Triangular Prism Calculator
V = 底面积 * 长；底为三角形 (½ab sin C 或 ½bh)。本地处理。可设置「底边」、「底高」、「棱柱长」。V = base area * length; triangular base ½bh. Processed locally. Settings: Base, Base height, Length.
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.
圆柱Cylinder Calculator
V = πr2h，侧面积 2πrh，全面积再加两底。本地处理。可设置「半径」、「高」。V = πr2h; lateral 2πrh; total adds both bases. Processed locally. Settings: Radius, Height.
长方体表面积计算器（含体积）Surface Area of a Cuboid Calculator (with Volume)
由长、宽、高求长方体表面积 2(lw + lh + wh) 和体积 lwh。边长须大于 0。本地处理。From length, width and height get the cuboid surface area 2(lw + lh + wh) and the volume lwh. Edges must be greater than 0. Processed locally.
筝形（菱形风筝）面积计算器Area of a Kite Calculator
筝形（两边对称的四边形）面积 = d₁d₂/2，其中 d₁、d₂ 是两条对角线。对角线须大于 0。本地处理。Kite area = d₁d₂/2 from the two diagonals (which are perpendicular). Diagonals must be greater than 0. Processed locally.
正多边形面积计算器（边长，含周长）Area of a Regular Polygon Calculator (Side Length, with Perimeter)
正 n 边形面积 A = (n s²) / (4 tan(π/n))，并给出周长 n s。边数 3-1000 的整数，边长大于 0。本地处理。Regular n-gon area A = (n s²) / (4 tan(π/n)), plus perimeter n s. Sides: whole number 3-1000; side length greater than 0. Processed locally.
半球体积计算器（含表面积）Volume of a Hemisphere Calculator (with Surface Area)
实心半球体积 V = (2/3) π r³，含底表面积 3 π r²（曲面 2 π r² + 底面 π r²）。半径须大于 0。本地处理。Solid hemisphere volume V = (2/3) π r³, and surface area including the base 3 π r² (curved 2 π r² + base π r²). Radius must be greater than 0. Processed locally.
可重复组合计算器（多重组合 C(n+r−1, r)）Combinations with Repetition Calculator (Multichoose C(n+r−1, r))
计算可重复组合数 C(n+r−1, r) = (n+r−1)! / (r!(n−1)!)，即从 n 种里取 r 个且允许重复、不计顺序。用精确大整数。本地处理。Combinations with repetition C(n+r−1, r) = (n+r−1)! / (r!(n−1)!): choose r from n types with repetition, order ignored. Exact big integers. Processed locally.
正比例计算器（y = kx）Direct Variation Calculator (y = kx)
由一组已知 (x, y) 求常数 k = y/x，再预测另一 x 对应的 y。已知 x 不能为 0。本地处理。可设置「已知 x」、「已知 y」、「求 y 的 x」。From one known (x, y) get k = y/x, then predict y at another x. Known x cannot be 0. Processed locally. Settings: Known x, Known y, x for y.
三角形外心计算器（外接圆圆心与半径）Circumcenter of a Triangle Calculator (Circumradius)
由平面三点坐标求外心（三边垂直平分线交点）和外接圆半径。共线时无外心。本地处理。From three planar points get the circumcenter (intersection of perpendicular bisectors) and circumradius. Collinear points have none. Processed locally.
三角形中位线计算器Midsegment of a Triangle Calculator
连接三角形两边中点的中位线平行于第三边且长度为其一半。输入第三边长即可。本地处理。The midsegment joining midpoints of two sides is parallel to the third side and half as long. Enter that third side length. Processed locally.
自然对数计算器（ln x 与 log₁₀ x）Natural Log Calculator (ln x and log₁₀ x)
计算 ln(x) = log_e(x)，并同时给出常用对数 log₁₀(x)。x 须大于 0。本地处理。可设置「x (>0)」。Computes ln(x) = log_e(x) and also common log log₁₀(x). x must be greater than 0. Processed locally. Settings: x (>0).
圆的切线长计算器Tangent Length to a Circle Calculator
圆外一点到切点的切线长 L = √(d² − r²)，d 为该点到圆心的距离，r 为半径（须 d > r）。本地处理。Tangent length from an external point L = √(d² − r²), with d = distance to centre and r = radius (need d > r). Processed locally.
正十二边形面积计算器Regular Dodecagon Area Calculator
正十二边形面积 A = 3 s² (2+√3)，并给出周长 12s。边长须大于 0。本地处理。Regular dodecagon area A = 3 s² (2+√3), plus perimeter 12s. Side length must be greater than 0. Processed locally.
正十边形面积计算器Regular Decagon Area Calculator
正十边形面积 A = (5/2) s² √(5+2√5)，并给出周长 10s。边长须大于 0。本地处理。Regular decagon area A = (5/2) s² √(5+2√5), plus perimeter 10s. Side length must be greater than 0. Processed locally.
圆柱侧面积计算器（含全面积）Lateral Surface Area of a Cylinder Calculator (with Total)
圆柱侧面积 2πrh，全面积 2πr(r+h)（含两个底面）。半径与高须大于 0。本地处理。Cylinder lateral area 2πrh and total surface 2πr(r+h) including both bases. Radius and height must be greater than 0. Processed locally.
钝角三角形判定器（锐角/直角/钝角）Obtuse Triangle Checker (Acute / Right / Obtuse)
由三边用余弦定理判定锐角、直角或钝角：比较最大边平方与另两边平方和。须满足三角不等式。本地处理。Classify acute, right or obtuse from three sides via the cosine rule: compare the largest side squared with the sum of the other squares. Must satisfy the triangle inequality. Processed locally.
矩形对角线计算器（含面积与周长）Rectangle Diagonal Calculator (with Area and Perimeter)
矩形对角线 d = √(l² + w²)，并给出面积 lw 与周长 2(l+w)。边长须大于 0。本地处理。Rectangle diagonal d = √(l² + w²), plus area lw and perimeter 2(l+w). Sides must be greater than 0. Processed locally.
不等边三角形计算器（海伦面积）Scalene Triangle Calculator (Heron Area)
由三边判定是否不等边（三边两两不等），并用海伦公式求面积与周长。须满足三角不等式。本地处理。Checks whether all three sides differ (scalene) and finds area by Heron plus the perimeter. Must satisfy the triangle inequality. Processed locally.
梯形棱柱体积计算器Trapezoidal Prism Volume Calculator
梯形棱柱体积 V = 梯形底面积 × 棱柱长，梯形面积 = (a+b)/2 × h。各边与高须大于 0。本地处理。Trapezoidal prism volume V = trapezoid area × length, with area = (a+b)/2 × h. Bases, height and length must be greater than 0. Processed locally.
二进制加法计算器Binary Addition Calculator
两个非负二进制整数相加，给出二进制和与十进制。可带 0b 前缀或下划线分隔。本地处理。Add two non-negative binary integers; show binary sum and decimal. Optional 0b prefix or underscore separators. Processed locally.
二进制除法计算器（整除与余数）Binary Division Calculator (Quotient and Remainder)
非负二进制整数整除：给出商、余数（二进制）及十进制验算。除数不能为 0。本地处理。Integer division of non-negative binaries: quotient, remainder (binary) and decimal check. Divisor cannot be 0. Processed locally.
二进制乘法计算器Binary Multiplication Calculator
两个非负二进制整数相乘，给出二进制积与十进制。可带 0b 前缀。本地处理。可设置「因数 A」、「因数 B」。Multiply two non-negative binary integers; show binary product and decimal. Optional 0b prefix. Processed locally. Settings: Factor A, Factor B.
二进制减法计算器Binary Subtraction Calculator
两个非负二进制整数相减，要求被减数 ≥ 减数，结果非负。给出二进制差与十进制。本地处理。Subtract non-negative binaries with minuend ≥ subtrahend (non-negative result). Shows binary difference and decimal. Processed locally.
欧氏距离（2D/3D）Euclidean Distance
2D 或 3D 两点距离。本地处理。可设置「维数」、「x₁」、「y₁」、「z₁」、「x₂」。2D or 3D distance between two points. Processed locally. Settings: Dimensions, x₁, y₁, z₁, x₂.
锐角三角形判定Acute Triangle Check
三边构成三角形且 a²+b²>c²（对最大边）则为锐角。本地处理。可设置「边 a」、「边 b」、「边 c」。Sides form a triangle and a²+b²>c² for the largest side → acute. Processed locally. Settings: Side a, Side b, Side c.
线段长度Length of a Line Segment
平面两点距离 √((x₂-x₁)²+(y₂-y₁)²)。本地处理。可设置「x₁」、「y₁」、「x₂」、「y₂」。Plane distance √((x₂-x₁)²+(y₂-y₁)²). Processed locally. Settings: x₁, y₁, x₂, y₂.
百分数转小数Percent to Decimal
小数 = 百分数 ÷ 100。本地处理。可设置「百分数 %」。Decimal = percent ÷ 100. Processed locally. Settings: Percent %.
三棱柱体积Triangular Prism Volume
V = (底边 × 高 / 2) × 棱长。本地处理。可设置「底边」、「三角形高」、「棱长」。V = (base × height / 2) × length. Processed locally. Settings: Base, Triangle height, Length.
智商百分位示意IQ Percentile (demo)
假设 IQ ~ N(100,15²)，用误差函数估百分位。本地处理。可设置「智商」。Assume IQ ~ N(100,15²); percentile via erf. Processed locally. Settings: IQ.
抛硬币概率Coin Flip Probability
n 次中恰好 k 次正面：C(n,k) / 2^n（公平硬币）。本地处理。可设置「次数」、「正面次数」。Exactly k heads in n fair flips: C(n,k)/2^n. Processed locally. Settings: Flips, Heads.
简单移动平均Simple Moving Average
对数列做窗口为 w 的 SMA。本地处理。可设置「数据（空格/逗号分隔）」、「窗口」。SMA of a series with window w. Processed locally. Settings: Data (space/comma separated), Window.
勾股定理Pythagorean Theorem
求直角三角形未知边。本地处理。可设置「求」、「边 a」、「边 b」、「斜边 c」。Solve the unknown side of a right triangle. Processed locally. Settings: Solve for, Leg a, Leg b, Hypotenuse c.
正四棱锥Square Pyramid
体积 V = a² h / 3；侧面斜高与侧面积示意。本地处理。可设置「底边」、「高」。Volume V = a² h / 3; slant height and lateral area demo. Processed locally. Settings: Base edge, Height.
胜率Winning Percentage
胜率 = (胜 + 0.5×平) / (胜+负+平)。本地处理。可设置「胜」、「负」、「平」。Win% = (wins + 0.5×draws) / (wins+losses+draws). Processed locally. Settings: Wins, Losses, Draws.
斜三角形（SAS）Oblique Triangle (SAS)
两边夹一角：第三边 c²=a²+b²-2ab cos C。本地处理。可设置「边 a」、「边 b」、「夹角 C °」。Two sides and included angle: c²=a²+b²-2ab cos C. Processed locally. Settings: Side a, Side b, Angle C °.