📚 Year 11 AQA Economics: Formula & Theorem Quick Reference Handbook | AQA 经济学公式定理速查手册
Mastering the essential formulas and theorems is the key to cracking Year 11 AQA Economics. This handbook gathers every quantitative tool and core economic principle you will need, from price elasticity to macroeconomic multipliers. Each entry is paired with a clear explanation in both English and Chinese to reinforce your understanding and exam technique.
掌握核心公式与定理是攻克 AQA 经济学 GCSE 的关键。这本速查手册汇集了你所需要的所有定量工具和核心经济原理，从价格弹性到宏观经济乘数。每个条目都配有清晰的中英双语解释，以加深理解并提升应试技巧。
1. Price Elasticity of Demand (PED) | 需求价格弹性
Price elasticity of demand measures the responsiveness of quantity demanded to a change in price. The formula is:
需求价格弹性衡量需求量对价格变化的反应程度。公式为：
PED = % change in quantity demanded ÷ % change in price
ice elastic; if PED < 1, demand is price inelastic; if PED = 1, demand is unit elastic.
PED 的数值始终取绝对值。若 PED > 1，需求富有价格弹性；若 PED < 1，需求缺乏价格弹性；若 PED = 1，需求具有单位弹性。
The midpoint (arc) method for calculating percentage changes gives more accurate results between two points:
使用中点法（弧弹性）计算两点间的百分比变化能得出更精确的结果：
% change in Qd = (Q₂ - Q₁) ÷ [(Q₁ + Q₂) ÷ 2] × 100
% change in P = (P₂ - P₁) ÷ [(P₁ + P₂) ÷ 2] × 100
Determinants of PED include the availability of substitutes, whether the good is a necessity or luxury, the proportion of income spent, and the time period considered. Revenue implications are vital: if demand is elastic, a price cut raises total revenue; if inelastic, a price rise increases total revenue.
影响需求价格弹性的因素包括替代品可得性、商品是必需品还是奢侈品、支出占收入的比例以及所考虑的时间段。收入效应至关重要：需求富有弹性时，降价会提高总收益；缺乏弹性时，提价会增加总收益。
2. Price Elasticity of Supply (PES) | 供给价格弹性
Price elasticity of supply shows how responsive quantity supplied is to a change in price.
供给价格弹性表示供给量对价格变化的反应程度。
PES = % change in quantity supplied ÷ % change in price
PES is always positive because of the law of supply. If PES > 1, supply is elastic; PES < 1 indicates inelastic supply. A PES of zero means perfectly inelastic supply (fixed quantity), while PES equal to infinity shows perfectly elastic supply.
根据供给定律，PES 始终为正。PES > 1 时供给富有弹性；PES < 1 时供给缺乏弹性。PES 为零表示供给完全无弹性（固定数量），PES 无穷大则表示供给完全有弹性。
Key determinants include the length of the production period, availability of spare capacity, ease of storing stock, and the time period. Supply becomes more elastic over time as firms can adjust all factors of production.
主要决定因素包括生产周期的长度、闲置产能的可用性、库存储存的难易程度以及时间跨度。随着时间的推移，厂商能够调整所有生产要素，供给弹性趋于增大。
3. Income Elasticity of Demand (YED) | 需求的收入弹性
Income elasticity of demand measures how demand changes as consumer income changes.
需求的收入弹性衡量需求如何随消费者收入变化而变化。
YED = % change in quantity demanded ÷ % change in income
For normal goods, YED is positive. A YED greater than 1 indicates a luxury good; between 0 and 1 is a necessity. For inferior goods, YED is negative — demand falls as income rises.
正常品 YED 为正。YED 大于 1 为奢侈品；介于 0 和 1 之间为必需品。低档品的 YED 为负——收入上升时需求反而下降。
Firms use YED to forecast sales during different stages of the economic cycle and to plan product portfolios. Understanding whether a product is normal or inferior helps businesses react to boom and recession scenarios.
企业用 YED 预测经济周期不同阶段的销售额，并规划产品组合。了解产品属于正常品还是低档品，有助于企业在繁荣与衰退情境下做出调整。
4. Cross Elasticity of Demand (XED) | 需求的交叉弹性
Cross elasticity of demand quantifies the relationship between the demand for one good and the price of another.
需求的交叉弹性量化一种商品的需求量与另一种商品价格之间的关系。
XED = % change in quantity demanded of Good A ÷ % change in price of Good B
A positive XED means the two goods are substitutes; a negative XED means they are complements. The larger the absolute value, the stronger the relationship. An XED of zero suggests independent goods.
XED 为正，表示两种商品互为替代品；XED 为负，表示互为互补品。绝对值越大，关系越强。XED 为零则表明商品彼此独立。
Firms analyse XED to anticipate the impact of competitors' pricing strategies on their own sales and to design bundle offers for complementary products. A significant substitute XED poses a competitive threat, while strong complementary XED can justify joint promotions.
企业通过分析 XED 预测竞争对手定价策略对自身销量的影响，并为互补品设计捆绑销售方案。替代品 XED 较大意味着竞争威胁，而互补品 XED 较强则可以支持联合促销。
5. Total, Average, and Marginal Revenue | 总收益、平均收益与边际收益
Revenue formulas are fundamental to profit‐maximising output decisions.
收益公式是利润最大化产量决策的基础。
Total Revenue (TR) = Price × Quantity sold
Average Revenue (AR) = TR ÷ Quantity = Price
Marginal Revenue (MR) = Change in TR ÷ Change in quantity
st or price maker, MR lies below the demand curve because to sell more, the firm must lower the price on all previous units.
在完全竞争下，价格恒定，因此 MR = AR = 需求曲线。对垄断者或定价者而言，MR 低于需求曲线，因为要卖出更多商品，厂商必须降低之前所有单位的价格。
evel, the gap between total revenue and total cost is greatest. Understanding the revenue curves helps identify the profit‐maximising level of sales.
利润最大化出现在 MR = MC（边际成本）处。在该产出水平，总收益与总成本之间的差额最大。理解收益曲线有助于确定利润最大化的销量。
6. Costs of Production | 生产成本
Cost analysis underpins supply decisions and efficiency measurement.
成本分析是供给决策和效率衡量的基础。
Total Cost (TC) = Total Fixed Cost (TFC) + Total Variable Cost (TVC)
Average Total Cost (ATC) = TC ÷ Quantity
Average Fixed Cost (AFC) = TFC ÷ Quantity
Average Variable Cost (AVC) = TVC ÷ Quantity
Marginal Cost (MC) = Change in TC ÷ Change in quantity
Fixed costs do not vary with output in the short run (e.g. rent), while variable costs change directly with production (e.g. raw materials). The short-run average total cost curve is usually U‑shaped because of the law of diminishing marginal returns.
在短期内，固定成本不随产出变动（如租金），而可变成本随生产直接变化（如原材料）。由于边际报酬递减规律，短期平均总成本曲线通常呈 U 形。
Long-run average cost curves can exhibit economies and diseconomies of scale. The minimum efficient scale is the lowest output at which a firm can produce so that its long-run average costs are minimised.
长期平均成本曲线可以展示规模经济与规模不经济。最低有效规模是指厂商能以最低长期平均成本进行生产的最低产量水平。
7. Profit and Break-Even | 利润与盈亏平衡
Profit is the reward for enterprise and the incentive to produce.
利润是对企业家精神的回报，也是生产激励。
Profit = Total Revenue - Total Cost
Normal profit is the minimum profit necessary to keep a firm in an industry; it occurs when TR equals TC (including opportunity cost). Supernormal profit (abnormal profit) arises when TR exceeds TC.
正常利润是维持厂商留在行业内的最低利润，当 TR = TC（包含机会成本）时出现。超额（异常）利润出现在 TR 大于 TC 时。
The break-even point is the output where total revenue exactly covers total costs. It can be calculated as:
盈亏平衡点是指总收益恰好弥补总成本时的产量。其计算公式为：
Break-even output = Total Fixed Costs ÷ (Selling Price per unit - Variable Cost per unit)
The denominator is also called the contribution per unit. Break-even analysis helps firms assess the viability of a product or project.
分母也被称为单位贡献毛利。盈亏平衡分析有助于企业评估产品或者项目的可行性。
8. Labour Productivity and Unemployment Rate | 劳动生产率与失业率
Productivity measures how efficiently inputs are converted into outputs. Labour productivity is a common metric.
生产率衡量投入转化为产出的效率。劳动生产率是常用指标。
Labour Productivity = Total Output ÷ Number of Workers
Alternatively, it can be expressed as output per hour worked. Higher productivity lowers unit costs and can raise living standards.
或者，可表示为每工作小时的产出。生产率提高可降低单位成本，并提升生活水平。
The unemployment rate captures the proportion of the labour force actively seeking but unable to find work.
失业率反映积极寻找工作但未果的劳动力所占比例。
Unemployment Rate = (Number of Unemployed ÷ Labour Force) × 100
The labour force comprises those employed plus those registered as unemployed. Types of unemployment include cyclical, structural, frictional, and seasonal. The claimant count and the Labour Force Survey are the two main UK measures.
劳动力包括就业者和登记失业者。失业类型包括周期性、结构性、摩擦性和季节性失业。英国的两种主要衡量指标为申领人数和劳动力调查数据。
9. Inflation and the Consumer Price Index (CPI) | 通货膨胀与消费者价格指数
Inflation is a sustained rise in the general price level. The annual inflation rate is calculated from the change in a price index.
通货膨胀指物价总水平持续上涨。年通胀率通过价格指数的变动来计算。
Inflation Rate = [(CPI this year - CPI last year) ÷ CPI last year] × 100
The CPI tracks the cost of a representative basket of goods and services. Each item is weighted according to its share in household spending. The basket and weights are updated annually to reflect changing consumption patterns.
CPI 追踪一篮子代表性商品和服务的费用。每种商品根据其在家庭支出中的份额赋予权重。篮子和权重每年更新，以反映消费模式的变化。
Demand-pull inflation occurs when aggregate demand grows faster than aggregate supply. Cost-push inflation is driven by rising production costs, such as wages or raw materials. High and unpredictable inflation can erode purchasing power, distort economic decisions, and hurt savers.
需求拉动型通货膨胀发生在总需求增长快于总供给时。成本推动型通货膨胀由工资或原材料等生产成本上升驱动。高且不可预期的通货膨胀会侵蚀购买力、扭曲经济决策并损害储蓄者利益。
10. Economic Growth and GDP | 经济增长与国内生产总值
Economic growth refers to an increase in the value of goods and services produced by an economy over time.
经济增长是指一个国家在一定时期内生产的商品与服务价值的增加。
Growth Rate = [(GDP in current year - GDP in previous year) ÷ GDP in previous year] × 100
Gross Domestic Product (GDP) can be measured by the output, income, or expenditure method. Real GDP strips out the effects of inflation, giving a more accurate picture of growth. GDP per capita is total GDP divided by population, reflecting average living standards.
国内生产总值（GDP）可用产出法、收入法或支出法计算。实际 GDP 剔除通胀影响，能更准确地反映增长。人均 GDP 是总 GDP 除以人口，反映平均生活水平。
Sustainable economic growth avoids excessive inflation and environmental degradation. Factors contributing to growth include increases in the quantity and quality of factors of production, technological progress, and improvements in efficiency.
可持续的经济增长要避免过度通货膨胀和环境退化。推动增长的因素包括生产要素数量与质量的提升、技术进步以及效率改善。
11. Exchange Rates and Currency Conversion | 汇率与货币换算
Exchange rates express the value of one currency in terms of another. They fluctuate due to supply and demand in foreign exchange markets.
汇率表示一种货币以另一种货币计价的价格，因外汇市场供需变化而波动。
Converting £ into a foreign currency: multiply the sterling amount by the exchange rate. Converting foreign currency back into £: divide the foreign amount by the exchange rate.
将英镑兑换为外币：用英镑金额乘以汇率。将外币兑换回英镑：用外币金额除以汇率。
Amount in foreign currency = Amount in £ × Exchange Rate (foreign per £)
Appreciation of the pound means it buys more units of foreign currency; depreciation means it buys fewer. A stronger pound makes exports more expensive and imports cheaper, worsening the current account balance. A weaker pound boosts exports and makes imports dearer, helping domestic producers but raising import costs.
英镑升值意味着能兑换更多外币；贬值则能兑换更少。强势英镑使出口更贵、进口更便宜，恶化经常账户收支。弱势英镑刺激出口，进口更昂贵，有利于本国生产者，但推高进口成本。
12. The Multiplier and the Marginal Propensity to Consume (MPC) | 乘数效应与边际消费倾向
The multiplier effect explains how an initial injection of spending can lead to a larger final increase in national income.
乘数效应解释初始支出注入如何导致国民收入出现更大幅度的最终增长。
Multiplier (k) = 1 ÷ (1 - MPC) or k = 1 ÷ MPS
s. The marginal propensity to save (MPS) is the proportion saved. Together, MPC + MPS = 1.
边际消费倾向（MPC）指额外收入中用于购买本国商品和服务的比例。边际储蓄倾向（MPS）是用于储蓄的比例。两者之和 MPC + MPS = 1。
MPC = Change in Consumption ÷ Change in Income
MPS = Change in Saving ÷ Change in Income
A higher MPC means a larger multiplier, making the economy more sensitive to changes in government spending, investment, or exports. The concept applies to any injection or withdrawal into the circular flow of income.
MPC 越大，乘数越大，经济对政府支出、投资或出口的变化越敏感。这一概念适用于收入循环流动中的任何注入或漏出。
13. Interest Rates, Saving, and Borrowing | 利率、储蓄与借贷
Interest rates are the reward for saving and the cost of borrowing. Central banks use the base rate to influence economic activity.
利率是对储蓄的回报，也是借贷的成本。中央银行通过基准利率影响经济活动。
While there is no single formula in the GCSE syllabus for interest calculations, understanding simple interest is tested:
虽然 GCSE 大纲没有单独的利息计算公式，但简单利息的计算会被考查：
Simple Interest = Principal × Rate × Time
For example, a 5% annual interest rate on £1,000 over 3 years yields £150 in interest. Higher interest rates tend to reduce consumption and investment, cool inflation, and appreciate the currency. Lower rates stimulate borrowing and spending but may fuel inflation.
例如，1000 英镑、5% 年利率、3 年期的简单利息为 150 英镑。较高利率往往抑制消费和投资、降低通胀并推动货币升值。较低利率刺激借贷与支出，但可能推高通胀。
Changes in the base rate affect mortgage payments, credit card debt, and business loans, altering aggregate demand. Students should be able to explain the transmission mechanism of monetary policy.
基准利率的变动影响房贷还款、信用卡债务和企业贷款，从而改变总需求。学生应能解释货币政策的传导机制。
14. Market Equilibrium, Surplus, and Shortage | 市场均衡、过剩与短缺
Equilibrium occurs where supply equals demand. The equilibrium price clears the market with no excess demand or excess supply.
均衡出现在供给等于需求时。均衡价格使市场出清，不存在超额需求或超额供给。
Equilibrium: Qd = Qs
When the market price is above equilibrium, quantity supplied exceeds quantity demanded, creating a surplus (excess supply). When the price is below equilibrium, quantity demanded exceeds quantity supplied, creating a shortage (excess demand). Prices tend to move toward equilibrium naturally, ceteris paribus.
当市场价格高于均衡时，供给量超过需求量，形成过剩（超额供给）。当价格低于均衡时，需求量超过供给量，形成短缺（超额需求）。在其他条件不变的情况下，价格自然趋向均衡。
The price mechanism performs three functions: signalling, incentive, and rationing. Excess demand signals producers to raise prices and increase output; excess supply signals them to cut prices and reduce output.
价格机制具有三大功能：信号功能、激励功能和配给功能。超额需求传递给生产者信号促使提价增产；超额供给则信号降价减产。
Published by TutorHao | Economics Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图