📚 AS Maths Unit 1 (Jan 20) Mark Scheme: High-Scoring Techniques | AS数学单元1 (2020年1月) 评分方案：高分技巧
The January 2020 AS Mathematics Unit 1 mark scheme offers far more than just the correct answers—it is a detailed map of how examiners award every single mark. By analysing the precise language, mark allocations, and examiner notes, you can reverse-engineer your exam technique to eliminate guesswork and systematically secure higher grades. This article breaks down the mark scheme’s structure into actionable, high-scoring strategies tailored for AS pure mathematics topics.
2020年1月AS数学单元1的评分方案提供的远不止正确答案，它是一份考官如何给每一分打分的详细地图。通过分析精确的措辞、分值分配和考官注释，你可以逆向设计自己的考试技巧，消除猜测，系统地获得更高分数。本文将评分方案的结构分解为针对AS纯数学主题的、可操作的高分策略。
1. Decoding the Mark Scheme Structure | 解码评分方案结构
Every mark in Unit 1 is classified as M (method), A (accuracy), or B (independent). A typical question might be labelled M1 A1, or B1 M1 A1. M marks reward a correct approach, even if the final answer is wrong; A marks demand correct numerical or algebraic results; B marks are for standalone statements or results that require no working. Recognising these categories helps you decide where to invest time and how to present your solution.
单元1中的每一分都被归类为 M（方法分）、A（准确性分）或 B（独立分）。典型题目可能标注 M1 A1 或 B1 M1 A1。M 分奖励正确的思路，即使最终答案有误；A 分要求精确的数值或代数结果；B 分针对无需展示过程的独立陈述或结果。辨别这些类别有助于你决定在何处投入时间以及如何呈现解题过程。
Examiners strictly adhere to a hierarchy: method first, then accuracy. You cannot earn an A mark without a valid M mark on the same strand, unless the question explicitly offers a B mark. For example, if you write a correct answer but no derivation, you might score only the B or final A if the scheme allows; otherwise, you lose the M marks and the related A marks. The January 2020 paper rewards fully displayed reasoning, so always show substitutions, rearrangements, and factorisations clearly.
考官严格遵循层级：先方法，后准确性。如果没有在同一条线上获得有效的 M 分，通常无法获得 A 分，除非题目明确提供了 B 分。例如，如果你写出了正确答案但没有推导过程，根据方案可能只能得到 B 分或最终 A 分；否则，你会失去 M 分以及与之关联的 A 分。2020年1月的试卷奖励充分展示的推理过程，所以务必清晰地写出代换、移项和因式分解的步骤。
2. Command Words and Their Real Meaning | 指令词及其真实含义
The mark scheme interprets command words with surgical precision. ‘Show that’ means you must demonstrate every algebraic step to reach the given result; skipping intermediate lines costs marks. ‘Hence’ indicates you must use the previous answer, and a different method will not score. ‘Find’ allows any valid method, but you must still document it. ‘State’ often signals a B mark—just give the answer without any working. Misreading ‘prove’ as ‘verify’ can derail an entire question because proof questions demand a chain of logical deductions, not just a single counterexample or numeric check.
评分方案以手术刀般的精确性解读指令词。“Show that” 意味着你必须展示每一个代数步骤以得到给定结果；跳过中间步骤会失分。“Hence” 表明你必须使用前一个答案，用其他方法不给分。“Find” 允许任何有效方法，但你仍需记录过程。“State” 通常意味着这是一个 B 分——只给出答案，无需过程。将 “prove” 误读为 “verify” 可能导致整个题目偏离方向，因为证明题要求逻辑推理的链条，而不仅是一个反例或数字验证。
In the January 2020 Unit 1, certain ‘Show that’ tasks were accompanied by a note in the scheme: ‘Must see the use of the identity’ or ‘Must include the expansion step’. This tells you exactly which line will trigger the M mark. Train yourself to highlight command words in the paper and recall from past mark schemes what specific action is expected. Practice rephrasing questions in your own words: ‘Show that’ becomes ‘I must derive, step by step, with explicit algebraic manipulation.’
在2020年1月的单元1中，某些 “Show that” 任务在方案中附有如下注释：“必须看到恒等式的使用”或“必须包含展开步骤”。这确切地告诉你哪一行会触发 M 分。训练自己在试卷中圈出指令词，并回想以往评分方案中要求的特定动作。练习用自己的话重新表述问题：“Show that” 变成“我必须逐步推导，并进行明确的代数操作”。
3. M Marks: The Gateway to Every Solution | M 分：每个解答的入口
Method marks are the exam equivalent of ‘partial credit’. They are awarded for a correct process, such as setting up an equation, applying the chain rule, or integrating with a constant of integration. Even if you make an arithmetic slip later, the M mark remains secure as long as your method is clear and appropriate. The January 2020 mark scheme shows that M marks are frequently given for quoting the correct formula and substituting values correctly, even before simplification.
方法分相当于考试中的“步骤分”。它们因使用了正确的过程而授予，例如建立方程、应用链式法则，或在积分时包含积分常数。即使随后出现计算错误，只要你的方法清晰且恰当，M 分仍然安全。2020年1月的评分方案显示，M 分经常在引用正确公式并正确代入数值时给出，甚至会在化简之前给出。
To guarantee M marks, structure your work so that the examiner can instantly identify the key method step. For a differentiation question, write the derivative operator over the function, then expand, then differentiate term by term. For a coordinate geometry problem, write down the formula for gradient explicitly before plugging in coordinates. Never embed the method inside a calculator scribble. A common pitfall: using a ‘canned’ approach without showing substitution—for example, writing the final discriminant < zero inequality without showing b² − 4ac. The scheme demands to see the expression b² − 4ac with the coefficients substituted.
为了确保 M 分，你的解答结构应让考官能立即识别关键方法步骤。对于微分题，先在函数上方写出导数运算符号，然后展开，再逐项求导。对于坐标几何题，在代入坐标之前明确写出斜率公式。绝不要把方法隐藏在用计算器草草写出的过程中。常见陷阱：使用“封装式”方法而不展示代换——例如，不展示 b² − 4ac 就直接写出判别式小于零的不等式。方案要求看到代入系数后的表达式 b² − 4ac。
Examiners’ reports for Unit 1 often remark: ‘Candidates who set out their work line by line scored highly, while those who jumped to the answer often lost M marks.’ Therefore, treat each line as a potential scoring point. If you make a mistake in one line but the method is evident, you preserve the M mark and can still earn subsequent independent marks.
单元1的考官报告常评论道：“逐行列出解题步骤的考生得分很高，而直接跳到答案的考生经常丢失 M 分。”因此，将每一行视为一个潜在得分点。如果某一行出错但方法明显，你保留了 M 分，并且仍然可以获取后续的独立分。
4. A Marks: Precision in Every Digit | A 分：每个数字的精确性
Accuracy marks demand that your final answer—and sometimes intermediate values—match the mark scheme exactly or fall within defined tolerance. In the January 2020 mark scheme, A marks are often ‘c.a.o.’ (correct answer only), meaning no equivalent forms are accepted unless specified. For example, if the answer is √5/2, writing 0.5√5 might not score the A mark unless the scheme lists it as an alternative. Always present answers in their simplest exact form, using fractions and surds rather than rounded decimals, unless the question explicitly asks for a decimal approximation.
准确性分要求最终答案（有时也包括中间值）与评分方案完全匹配或落在指定容差内。在2020年1月的评分方案中，A 分通常是“c.a.o.”（仅限正确答案），意味着除非特别说明，否则不接受其他等价格式。例如，如果答案是 √5/2，写成 0.5√5 可能拿不到 A 分，除非方案将它列为替代答案。除非问题明确要求小数近似值，否则始终以最简精确形式给出答案，使用分数和根式而不是四舍五入的小数。
A common costly error is the misuse of notation that invalidates an A mark, such as omitting brackets around negative numbers when squaring. The January 2020 scheme penalised missing absolute value signs in logarithm or modulus contexts. Also, watch for trailing zeros after a decimal—if the scheme says 3.14 and you write 3.140, it may be considered incorrect if the question required 3 significant figures. Cultivate the habit of checking your final line against the command word: if the question says ‘give your answer in the form a + b√c’, write it exactly in that arrangement, even if other forms are mathematically identical.
常见且代价高昂的错误是符号的误用导致 A 分无效，例如平方时负数周围漏掉括号。2020年1月的方案规定，在对数或模运算中缺少绝对值符号会被扣分。同时要注意小数点后多余的零——如果方案答案是 3.14，而你写成 3.140，若题目要求3位有效数字可能被判错。养成习惯，根据指令词检查你的最后一行：如果题目说“以 a + b√c 的形式给出答案”，就严格按照这种格式书写，即使其他形式在数学上相同。
Use the mark scheme to identify ‘magic numbers’ that must appear. For a binomial expansion question, the scheme lists required terms; missing a coefficient loses the A mark even if the rest is correct. In trigonometry, providing a second solution outside the specified range can also invalidate the A mark, as the scheme typically requires only the solutions within 0° ≤ x < 360°.
利用评分方案识别必须出现的“魔数”。在二项式展开题中，方案列出了必需的项；漏掉一个系数就会失去 A 分，即使其余部分正确。在三角学中，提供超出指定区间的第二个解也会使 A 分无效，因为方案通常只要求在 0° ≤ x < 360° 内的解。
5. B Marks: Quick Wins and Standalone Points | B 分：快速得分点与独立分
B marks are the jewels of the mark scheme: they require no working and are often awarded for a single correct statement, graph annotation, or answer. In the January 2020 paper, B marks commonly appeared in multiple choice–style questions embedded within longer tasks, such as identifying the shape of a curve, stating an asymptote, or giving the range of a function. These marks can be banked quickly if you have strong conceptual recall.
B 分是评分方案中的宝石：它们不需要步骤，通常因单个正确的陈述、图形标注或答案而给出。在2020年1月的试卷中，B 分常出现在包含于较长题目内的选择题式问题中，例如识别曲线形状、说出渐近线或给出函数的值域。如果你有扎实的概念记忆，这些分数可以快速收入囊中。
However, a B mark is all-or-nothing; if your answer is slightly wrong, you get zero—there is no follow-through. For a function’s range written as y > 2 instead of y ≥ 2, the B mark is lost. The January 2020 mark scheme explicitly stated ‘Accept any equivalent form’ for some B marks, such as interval notation, but for others it required a specific set notation. To maximise B marks, memorise the exact phrasing from your textbook for definitions: ‘A function is increasing if f'(x) ≥ 0’ and not just ‘when derivative positive’.
然而，B 分是非对即错；如果你的答案稍有偏差，就是零分——没有后续给分。将函数值域写成 y > 2 而非 y ≥ 2，B 分就会丢失。2020年1月的评分方案明确指出，某些 B 分“接受任何等价形式”，如区间表示法，但另外一些则要求特定的集合表示法。要想把 B 分拿满，就把课本中对定义的精确表述记下来：“函数递增当 f'(x) ≥ 0”，而不仅仅是“当导数为正时”。
You can often pre-empt B marks by studying the specification. For instance, knowledge of the graph of y = 1/x might earn a B mark for the asymptote x = 0, y = 0. On the day, sketch a quick graph in the margin if it helps you confirm the correct answer before committing it to the answer line.
通过学习考纲，你常常可以提前预判 B 分。例如，了解 y = 1/x 的图像可能会让你因说出渐近线 x = 0, y = 0 而获得 B 分。考试时，在空白处快速画个草图有助于你在把答案填到横线上之前确认是否正确。
6. Mastering Proof Questions with the Mark Scheme | 利用评分方案掌握证明题
Proof questions in Unit 1 carry a distinct mark structure: typically M1 for setting up the statement, M1 for a correct algebraic manipulation, and A1 for a rigorous conclusion. The January 2020 mark scheme reveals that examiners look for a clear starting statement, such as ‘Assume that n is an even integer, then n = 2k’, and a clear closing line: ‘Therefore, n² is divisible by 4’. Without the conclusion, you may lose the final A mark.
单元1中的证明题有独特的给分结构：通常是 M1 用于设定陈述，M1 用于正确的代数操作，A1 用于严谨的结论。2020年1月的评分方案显示，考官期待一个明确的起始陈述，如“假设 n 为偶数，则 n = 2k”，并有一个清晰的结束语：“因此，n² 能被 4 整除”。没有结论，你可能失去最后的 A 分。
A frequent mistake is using the same variable for two different cases or forgetting to cover all required cases. The mark scheme penalises incomplete exhaustion or deduction. If proving that √2 is irrational, the argument by contradiction must show that if √2 = p/q in lowest terms, then p and q are both even, leading to a contradiction. The January 2020 scheme awarded a method mark for the step ‘p² = 2q² ⇒ p is even’ and another for the symmetrical reasoning on q; the final A mark required the statement ‘contradiction, therefore √2 is irrational’.
常见错误是对两个不同情形使用同一变量，或忘记涵盖所有要求的情形。评分方案会对不完整的穷举或演绎推理扣分。若证明 √2 为无理数，反证法必须展示：如果 √2 = p/q 且已约至最简，那么 p 和 q 均为偶数，导出矛盾。2020年1月的方案对“p² = 2q² ⇒ p 为偶数”这一步骤给出方法分，对 q 的对称推理给出另一个方法分；最后的 A 分要求陈述“矛盾，故 √2 是无理数”。
To train, rewrite mark scheme solutions as a bullet-point proof structure, highlighting the logical connectors: ‘Assume the opposite…’, ‘Then…’, ‘Thus…’, ‘This contradicts…’, ‘Hence the original statement holds.’ Mimicking this flow guarantees you hit all the expected checkpoints.
要训练自己，可以把评分方案中的解答重写为分点证明结构，突出逻辑连接词：“假设反面…”“则…”“因此…”“这与…矛盾”“故原命题成立。”模仿这种流程可以保证你踩到所有预期的得分点。
7. Common Pitfalls in Pure Mathematics Topics | 纯数学主题的常见陷阱
The January 2020 Unit 1 mark scheme highlights several recurring errors across topics. In algebra, students often mishandle indices: they misinterpret x√x as x³/² but then incorrectly simplify (x√x)² to x³ rather than x³. The scheme insists on seeing the correct application of index laws: xᵃ × xᵇ = xᵃ⁺ᵇ. In quadratics, forgetting to set the discriminant correctly for ‘equal roots’ or ‘no real roots’ leads to lost M marks; the mark scheme explicitly links the word ‘equal’ to b² − 4ac = 0.
2020年1月单元1的评分方案突显了多个跨主题的反复错误。在代数中，学生常错误处理指数：他们将 x√x 理解为 x³/²，但随后错误地将 (x√x)² 化简为 x³ 而非 x³。方案要求看到指数法则的正确应用：xᵃ × xᵇ = xᵃ⁺ᵇ。在二次方程中，忘记为“相等实根”或“无实根”正确设定判别式会导致丢失 M 分；评分方案明确将“相等”与 b² − 4ac = 0 联系起来。
In calculus, a subtle trap is the omission of the integration constant in indefinite integrals unless the question says ‘find an expression for y’. The January 2020 scheme deducted an A mark if ‘+ C’ was missing after integration when finding a general solution. For differentiation, confusing the derivative of ln(2x) as 1/(2x) instead of 1/x is a classic error. The scheme relies on the chain rule evidence: writing dy/dx = (1/(2x)) × 2, so marks are awarded for showing the derivative of the inside function.
在微积分中，一个微妙的陷阱是除非题目说“求 y 的表达式”，否则在不定积分中漏掉积分常数。2020年1月的方案规定，在求通解时，积分后漏掉 ‘+ C’ 会被扣除 A 分。在微分中，将 ln(2x) 的导数误认为 1/(2x) 而非 1/x 是一个经典错误。方案依赖链式法则的证据：写出 dy/dx = (1/(2x)) × 2，所以对写出内层函数导数会奖励分数。
Word-heavy questions on sequences and series demand correct use of ‘nth term’ notation. Candidates often write the sum formula instead of aₙ. The mark scheme for January 2020 awarded M1 only if the expression explicitly began with uₙ = … or a = … and d = …, separating the term formula from the sum. Always read the question stem: it may say ‘Find the nth term’ or ‘Find the sum of the first n terms’—treating them interchangeably is fatal.
关于数列和级数的文字密集型问题要求正确使用“第 n 项”符号。考生常写出求和公式而非 aₙ。2020年1月的评分方案规定，只有明确以 uₙ = … 或 a = … 且 d = … 开始的表达式才能得到 M1，将通项公式与求和公式分开。务必阅读题干：它可能写的是“求第 n 项”或“求前 n 项和”——把它们混为一谈是致命的。
8. Leveraging the Mark Scheme for Targeted Revision | 利用评分方案进行针对性复习
The January 2020 mark scheme is not just a post-exam checker; it is a pre-exam tool. Use it to categorise error types: are you losing M marks because your method is invisible, or A marks because of algebraic slips? Create a personal error log. For each missed mark, write down the exact step you omitted or miswrote, then practise similar questions while consciously including that step. The scheme’s ‘Notes’ column often gives alternative methods—study these to see if you are over-relying on a single technique that might fail in an unfamiliar context.
2020年1月的评分方案不仅是考后检查工具，也是考前工具。用它来将错误分类：你是因为方法不可见而丢 M 分，还是因为代数运算失误丢 A 分？建立个人错题日志。对于每个丢掉的分数，写下你遗漏或写错的确切步骤，然后有意识地练习包含该步骤的类似题目。方案的“注释”栏常提供替代方法——研究这些，看看你是否过度依赖某一种在陌生情境下可能失效的技巧。
Organise your revision sessions around ‘mark-scheme-focused drills’. Take a past paper, cover the solutions, and attempt a question. Immediately after, reveal only the mark scheme’s allocation for that question. Score yourself on method first: did I earn M1? If not, review the required step. Then check A marks: is my final answer exactly as shown? If not, find the algebraic slip. This immediate feedback loop builds the examiner’s perspective into your intuition.
围绕“评分方案聚焦练习”安排你的复习环节。拿一份历年真题，遮住答案，尝试答题。完成后，仅展示该题的评分方案分值分配。先按方法给自己打分：我拿到了 M1 吗？如果没有，回顾必需的步骤。然后核查 A 分：我的最终答案与方案所示完全一致吗？如果不一致，找出代数运算失误。这种即时反馈循环能将考官的视角内化为你的直觉。
Recognise that some B marks are memory-based: you either know the derivative of tan x or you don’t. Use the scheme to compile a list of ‘must-know facts’ for Unit 1—trig exact values, log laws, standard derivatives and integrals—and test them daily. The January 2020 scheme consistently awarded B marks for writing sin(π/3) = √3/2 in coordinate geometry or calculus contexts.
要意识到，有些 B 分是基于记忆的：你要么知道 tan x 的导数，要么不知道。利用方案整理一份单元1的“必背知识点”列表——特殊三角函数值、对数法则、标准导数和积分——并每天测试自己。2020年1月的方案在坐标几何或微积分情境中，持续为写出 sin(π/3) = √3/2 而给出 B 分。
9. Time Management and Paper Strategy | 时间管理与试卷策略
The January 2020 mark scheme reveals that the final 2–3 marks of a multi-part question often depend on a chain of earlier results. If you are stuck on part (a), you cannot afford to waste 15 minutes and leave no time for part (b) and (c) which may be easier. Adopt a ‘first-pass, second-pass’ strategy: on first pass, answer every part that you can do confidently, securing the quick B marks and setting up the M marks. Leave blanks for tough parts, but write down any initial formula or substitution—these can earn M marks even if you don’t finish.
2020年1月的评分方案揭示，多部分题目中最后2到3分往往依赖前面结果形成的链条。如果你在 (a) 部分卡住，不能浪费15分钟导致没时间做可能更简单的 (b) 和 (c)。采用“第一遍、第二遍”策略：第一遍，完成所有你有把握的部分，拿到速成的 B 分并为 M 分打下基础。难的部分先空着，但写下任何初始公式或代换——这些即使你没做完也能获得 M 分。
Use the mark scheme’s total marks per question as a time guide: if a question carries 6 marks, spend no more than 7–8 minutes. In the January 2020 paper, a 4-mark question that was purely a ‘Find’ with a B mark for stating a property required about 4 minutes; spending 10 minutes on it erodes time from later higher-mark questions. Train with a visible stopwatch, forcing yourself to move on once the allocated time elapses.
将评分方案中每道题的总分作为时间指南：如果一道题6分，花费不超过7–8分钟。在2020年1月的试卷中，一道纯粹是“Find”并带有一个陈述性质的 B 分的4分题大约需要4分钟；花10分钟在上面会挤占后面高分题目的时间。使用可见的秒表进行训练，迫使自己在分配时间用完后立即跳题。
In the reading time, scan the paper and identify the questions with isolated B marks—these are your quickest gains. Also note which questions require ‘Show that’ because you must write meticulous steps. Plan your order: tackle B-mark-heavy questions first, then M-A sequence questions, leaving proof or extended reasoning until you have momentum and confidence.
在阅卷时间里，扫视试卷，找出含有独立 B 分的题目——这是你最快的得分点。同时留意哪些题目要求“Show that”，因为你必须写出精细的步骤。规划你的答题顺序：先做 B 分密集的题目，然后是 M-A 连续题，把证明或拓展推理留到你已经进入状态、充满信心的时候再做。
10. Case Study: A Typical Question Breakdown | 案例分析：典型题目分解
Consider a question from the January 2020 style: ‘Show that the equation of the tangent to the curve y = x² − 4x + 7 at the point where x = 3 is y = 2x − 2.’ The mark scheme would allocate: M1 for finding the derivative dy/dx = 2x − 4; M1 for evaluating gradient at x = 3: m = 2; M1 for finding the y-coordinate: y = 3² − 4(3) + 7 = 4; M1 for using y − y₁ = m(x − x₁) with (3, 4) and m = 2; A1 for correctly simplifying to y = 2x − 2; B1 perhaps for explicitly stating the tangent equation in the required form. Without showing the substitution step for y₁, you might lose an M mark, even if you write the correct line. The scheme expects to see y − 4 = 2(x − 3) written explicitly.
试举一个2020年1月风格的题目：“证明曲线 y = x² − 4x + 7 在 x = 3 处的切线方程为 y = 2x − 2。”评分方案会如此分配：M1 求导数 dy/dx = 2x − 4；M1 计算 x = 3 处的梯度 m = 2；M1 求 y 坐标 y = 3² − 4(3) + 7 = 4；M1 对 (3, 4) 和 m = 2 使用 y − y₁ = m(x − x₁)；A1 正确化简得到 y = 2x − 2；或许还有一个 B1 用于明确提出所需形式的切线方程。若不展示 y₁ 的代换步骤，即使你写出了正确的式子，也可能失去一个 M 分。方案期望明确写出 y − 4 = 2(x − 3)。
This breakdown illustrates the granularity of expectation. A student who writes ‘gradient = 2(3) − 4 = 2, then y − 4 = 2(x − 3) ⇒ y = 2x − 2’ scores full marks because every M step is visible. Another who jumps directly to ‘y = 2x − 2’ after finding the gradient risks losing the M1 for substituting into the line formula, because the examiner cannot see whether the method was used or copied from elsewhere. Let the mark scheme teach you the minimum visible lines required.
这一分解体现了考纲期望的精细程度。一位学生写出 “gradient = 2(3) − 4 = 2, then y − 4 = 2(x − 3) ⇒ y = 2x − 2” 会得满分，因为每个 M 步骤都可见。另一位在求出梯度后直接跳到 “y = 2x − 2” 则有可能失掉将数值代入直线公式的 M1，因为考官无法判断该方法是真用过还是从别处抄来的。让评分方案教会你至少需要展示哪些行。
Apply this principle to all question types: for integration to find area, the scheme demands seeing the definite integral set-up, the antiderivative with limits substituted, and the final subtraction. For series, it demands writing Sₙ formula, substitution of n and d, and then simplification. In every case, align your answer with the expected checkpoint.
将这一原则应用于所有题型：对于求面积的积分，方案要求看到定积分的设定、代入上下限的原函数以及最后的减法运算。对于级数，方案要求写出 Sₙ 公式，代入 n 和 d，然后化简。无论何种情况，都要让你的解答与预期的评分点吻合。
11. Numerical Accuracy and Rounding | 数值精确性与舍入
The January 2020 scheme is strict on rounding and truncation. For questions that specify ‘give your answer to 3 significant figures’, an answer of 12.3 is acceptable, but 12.30 is not unless the last digit is significant. Similarly, if an intermediate value is used in subsequent parts, the scheme often awards ‘ft’ (follow through) marks but only if the candidate has used their own consistent value and not a re-typed approximation that differs from the scheme’s stored value. Always store exact values in your calculator and use them for further calculations; never round prematurely.
2020年1月的方案在舍入和截断上非常严格。对于指定“答案保留3位有效数字”的题目，12.3 可以接受，但 12.30 不可接受，除非最后一位是有效的。同样，如果中间值被用于后续部分，方案通常会给“ft”（跟随）分，但前提是考生使用了他们自己一致的值，而不是一个与方案存储值不符的重新录入的近似值。始终在计算器中存储精确值并用于进一步计算；绝不要提前舍入。
In trigonometric equations solved in degrees, the mark scheme dictates the acceptable range of answers. For a solution that is 23.6° after rounding from 23.58°, writing 23.58° might score, but 23.6° is the expected form; however, both might be accepted if the question simply says ‘give your answer to 1 decimal place’. Yet, the scheme sometimes includes a specific note: ‘awrt 23.6’ (anything which rounds to 23.6). Understanding ‘awrt’ means you are safe as long as your unrounded value rounds correctly. Learn the language of
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