📚 Formula & Theorem Quick-Reference Guide for Year 11 Eduqas Economics | Year 11 Eduqas 经济：公式定理速查手册
This revision booklet provides a concise, exam-focused summary of all essential formulas and quantitative theorems for the Year 11 Eduqas GCSE Economics syllabus. Use it to master calculations for elasticity, costs, revenues, macroeconomic indicators, and international trade. Each section pairs English explanation with Chinese translation so you can revise bilingually and deepen understanding.
本复习手册为 Year 11 Eduqas GCSE 经济学大纲中所有关键公式与定量定理提供简洁、针对考试的速查总结。可用于掌握弹性、成本、收入、宏观经济指标和国际贸易等计算。每个部分均采用英文说明与中文翻译配对，帮助你进行双语复习并加深理解。
1. Price Elasticity of Demand (PED) | 需求价格弹性
Price elasticity of demand (PED) measures the responsiveness of quantity demanded to a change in the good's own price.
需求价格弹性衡量需求量对商品自身价格变化的反应程度。
PED = % change in quantity demanded / % change in price
Percentage change is calculated as: (New value − Original value) / Original value × 100%.
百分比变化计算为：(新值 − 原值) / 原值 × 100%。
easure when using two points: PED = (Q₂ − Q₁) / ((Q₂ + Q₁)/2) ÷ (P₂ − P₁) / ((P₂ + P₁)/2).
当使用两个数据点时，中点法提供更准确的度量：PED = (Q₂ − Q₁) / ((Q₂ + Q₁)/2) ÷ (P₂ − P₁) / ((P₂ + P₁)/2)。
PED is usually negative, but economists often ignore the sign and use absolute values.
PED 通常为负值，但经济学家常忽略负号并使用绝对值。
rongly to price). If PED < 1, demand is inelastic. If PED = 1, demand has unit elasticity.
若 PED 绝对值 > 1，需求富有弹性（数量对价格反应强烈）。若 PED < 1，需求缺乏弹性。若 PED = 1，需求具有单位弹性。
izontal demand curve); perfectly inelastic demand gives PED = 0 (a vertical demand curve).
完全弹性需求对应 PED = ∞（水平需求曲线）；完全无弹性需求对应 PED = 0（垂直需求曲线）。
Example: If a 10% price rise cuts quantity demanded by 20%, PED = −20% / 10% = −2, so demand is elastic (absolute value 2).
例题：如果提价10%导致需求量下降20%，PED = −20% / 10% = −2，因此需求富有弹性（绝对值2）。
2. Price Elasticity of Supply (PES) | 供给价格弹性
Price elasticity of supply (PES) measures the responsiveness of quantity supplied to a change in the good's own price.
供给价格弹性衡量供给量对商品自身价格变化的反应程度。
PES = % change in quantity supplied / % change in price
PES is usually positive because a higher price normally encourages firms to supply more.
PES 通常为正值，因为更高的价格通常鼓励企业增加供给。
upply is elastic. If PES < 1, supply is inelastic. If PES = 1, supply has unit elasticity.
如果 PES > 1，供给富有弹性。如果 PES < 1，供给缺乏弹性。如果 PES = 1，供给具有单位弹性。
Short-run supply tends to be more inelastic; long-run supply is more elastic as firms can adjust capacities.
短期供给往往更缺乏弹性；长期供给更富有弹性，因为企业可以调整产能。
Example: A 15% price increase leads to a 15% rise in quantity supplied – PES = 15% / 15% = 1 (unit elastic supply).
例题：价格上涨15%使供给量增加15% – PES = 15% / 15% = 1（单位弹性供给）。
3. Income Elasticity of Demand (YED) | 需求收入弹性
Income elasticity of demand (YED) measures how quantity demanded changes as consumer income changes.
需求收入弹性衡量需求量如何随消费者收入变化而变化。
YED = % change in quantity demanded / % change in income
Normal goods have a positive YED. For a necessity, 0 < YED < 1; for a luxury, YED > 1.
正常品的 YED 为正。对于必需品，0 < YED < 1；对于奢侈品，YED > 1。
Inferior goods have a negative YED: demand falls as income rises.
低档品具有负的 YED：收入增加时需求下降。
Firms use YED to forecast how sales respond to changes in the economic cycle.
企业利用 YED 预测销售额如何随经济周期变化。
Example: If a 4% rise in income causes a 2% increase in demand for a good, YED = 2% / 4% = 0.5 (necessity).
例题：若收入增长4%导致某商品需求增加2%，YED = 2% / 4% = 0.5（必需品）。
4. Cross Elasticity of Demand (XED) | 需求交叉弹性
Cross elasticity of demand (XED) measures how the quantity demanded of one good (A) responds to a change in the price of another good (B).
需求交叉弹性衡量一种商品(A)的需求量对另一种商品(B)价格变化的反应。
XED = % change in quantity demanded of Good A / % change in price of Good B
Substitute goods have a positive XED: a rise in the price of B increases demand for A.
替代品具有正的 XED：B 的价格上涨会增加对 A 的需求。
Complementary goods have a negative XED: a rise in the price of B reduces demand for A.
互补品具有负的 XED：B 的价格上涨会减少对 A 的需求。
Unrelated goods have an XED close to zero.
不相关商品的 XED 接近于零。
Example: If the price of tea rises by 8% and the demand for coffee rises by 6%, XED = 6% / 8% = 0.75 (substitutes).
例题：茶叶价格上升8%，咖啡需求上升6%，则 XED = 6% / 8% = 0.75（替代品）。
5. Costs, Revenue and Profit | 成本、收入与利润
Total cost (TC) is the sum of all expenses a firm incurs. It equals total fixed cost (TFC) plus total variable cost (TVC).
总成本是企业发生的所有支出之和，等于总固定成本加总可变成本。
TC = TFC + TVC
Average cost (AC) is the cost per unit of output.
平均成本是每单位产出的成本。
AC = TC / Quantity (Q)
Total revenue (TR) is the income from selling goods.
总收入是销售商品带来的收入。
TR = Price × Quantity sold
Profit is the residual after covering all costs.
利润是覆盖所有成本后的剩余。
Profit = TR − TC
= TC, the firm breaks even (normal profit). If TR > TC, the firm earns supernormal profit.
当 TR = TC 时，企业盈亏平衡（正常利润）。若 TR > TC，企业获得超额利润。
Example: A business sells 200 units at £15 each, with TFC = £1,000 and TVC = £1,200. TC = £2,200, TR = £3,000, Profit = £800.
例题：一家企业以每件£15销售200单位，TFC = £1,000，TVC = £1,200。TC = £2,200，TR = £3,000，利润 = £800。
6. Productivity | 劳动生产率
Labour productivity measures output per worker over a given period. Higher productivity can lower average costs and improve competitiveness.
劳动生产率衡量既定时期内每个工人的产出。较高的生产率可以降低平均成本并提高竞争力。
Labour productivity = Total output per period / Number of workers
Output can be measured in physical units or value terms. Productivity can also be expressed as output per hour worked.
产出可用实物数量或价值额衡量。生产率也可表示为每小时工作的产出。
When productivity rises, a business can produce more with the same number of workers, lifting profits or allowing price cuts.
当生产率提高时，企业能用相同数量的工人生产更多产品，从而增加利润或实现降价。
es 10,000 units a week. Labour productivity = 10,000 / 50 = 200 units per worker per week.
例题：一家工厂有50名工人，每周生产10,000件产品。劳动生产率 = 10,000 / 50 = 每周每名工人200件。
7. Inflation Rate | 通货膨胀率
Inflation is a sustained rise in the general price level. The main measure in the UK is the Consumer Prices Index (CPI).
通货膨胀是总体价格水平的持续上涨。英国主要使用消费者价格指数 (CPI) 衡量。
Inflation rate = (CPI current year − CPI previous year) / CPI previous year × 100%
A low and stable inflation rate (e.g., the 2% target) supports economic confidence. High or deflationary rates can be harmful.
低而稳定的通胀率（如2%目标）有助于经济信心。高通胀或通缩则可能带来损害。
If CPI rises from 120 to 126, the inflation rate = (126 − 120) / 120 × 100% = 5%.
若 CPI 从120升至126，通货膨胀率 = (126 − 120) / 120 × 100% = 5%。
Governments and central banks use high-frequency CPI data to set interest rates and fiscal policy.
政府和央行利用高频 CPI 数据制定利率和财政政策。
8. Unemployment Rate | 失业率
The unemployment rate indicates the percentage of the labour force that is without work but actively seeking employment.
失业率表示劳动力中没有工作但积极寻找工作的人所占的百分比。
Unemployment rate = (Number of unemployed / Labour force) × 100%
The labour force includes all people in employment plus those unemployed. Students, retirees and those not looking for work are not counted.
劳动力包括所有就业者加上失业者。学生、退休人员和没有找工作的人不计入内。
A rising unemployment rate often signals economic slowdown; a very low rate may indicate a tight labour market and upward wage pressure.
失业率上升通常预示经济放缓；极低的失业率可能表明劳动力市场紧张和工资上涨压力。
on unemployed and a labour force of 30 million, the unemployment rate = (1.5m / 30m) × 100% = 5%.
例题：如果一个国家有150万失业者，劳动力为3000万，失业率 = (150万 / 3000万) × 100% = 5%。
9. Gross Domestic Product (GDP) | 国内生产总值
GDP measures the total market value of all final goods and services produced within a country in a given period.
GDP 衡量一定时期内一国境内生产的所有最终商品和服务的市场总价值。
GDP = C + I + G + (X − M)
Where C = consumption, I = investment, G = government spending, X = exports, M = imports.
其中 C = 消费，I = 投资，G = 政府支出，X = 出口，M = 进口。
GDP does not. GDP per capita = GDP / population, and is used to compare living standards.
实际 GDP 剔除了通胀影响，名义 GDP 则没有。人均 GDP = GDP / 人口，用于比较生活水平。
Economic growth rate is measured as the percentage change in real GDP:
经济增长率以实际 GDP 的百分比变化衡量：
wth rate = (Real GDP current year − Real GDP previous year) / Real GDP previous year × 100%
Government policy often targets steady GDP growth to create jobs and raise tax revenues.
政府政策通常以稳定 GDP 增长为目标，以创造就业并增加税收。 Published by TutorHao | Year 11 Economics Revision Series | aleveler.com
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