Contoh Soal Elastisitas Permintaan Parsial Ke-2

Introduction

This tutorial will guide you through the concept of partial elasticity of demand, particularly focusing on examples that elucidate its application. Understanding partial elasticity is crucial for analyzing how the quantity demanded of a good responds to changes in the price of that good or related goods. This tutorial is based on the video by Devi Ayugi Rukmana and aims to simplify the concepts presented.

Step 1: Understanding Elasticity of Demand

• Elasticity of demand measures how much the quantity demanded of a good responds to changes in price or income.
• Partial elasticity specifically examines how the demand for one good changes in response to the price changes of another good.
• Key formula to remember: [ E_{xy} = \frac{\Delta Q_x / Q_x}{\Delta P_y / P_y} ]
  • (E_{xy}) = partial elasticity of demand for good X with respect to the price of good Y
  • (\Delta Q_x) = change in quantity demanded of good X
  • (\Delta P_y) = change in price of good Y

Step 2: Calculating Partial Elasticity

• Follow these steps to calculate partial elasticity:
  1. Identify the goods involved: Determine which good's demand is being analyzed and which related good's price is changing.
  2. Collect data: Gather data on the quantity demanded for good X at two different price points of good Y.
  3. Calculate changes:
     • Determine the change in quantity ((\Delta Q_x)) and the average quantity ((Q_x)).
     • Determine the change in price ((\Delta P_y)) and the average price ((P_y)).
  4. Apply the formula: Substitute the values into the elasticity formula to find (E_{xy}).

Step 3: Interpreting Results

• Analyze the elasticity value:
  • If (E_{xy} > 1), demand is elastic (quantity demanded changes significantly with price change).
  • If (E_{xy} < 1), demand is inelastic (quantity demanded changes little with price change).
  • If (E_{xy} = 1), demand is unitary elastic (percentage change in quantity demanded equals percentage change in price).

Step 4: Practical Examples

• Example 1: Assume the price of coffee increases from $2 to $3, and the quantity demanded decreases from 100 cups to 80 cups:

  • Calculate (\Delta Q_x = 80 - 100 = -20)
  • Calculate (\Delta P_y = 3 - 2 = 1)
  • Average quantity (Q_x = (100 + 80) / 2 = 90)
  • Average price (P_y = (2 + 3) / 2 = 2.5)
  • Apply the formula: [ E_{coffee} = \frac{-20 / 90}{1 / 2.5} = \frac{-0.222}{0.4} \approx -0.555 ]
  • Interpretation: A price increase leads to a decrease in demand, indicating inelastic demand.

• Example 2: Consider the price of tea rising from $1 to $1.50, leading to a demand change from 150 to 100 cups:

  • Calculate similarly to Example 1 to find the elasticity.

Conclusion

Partial elasticity of demand is a vital concept in economics that helps businesses and economists understand consumer behavior. By following the steps outlined in this tutorial, you can calculate and interpret the partial elasticity of demand, allowing for informed decisions in pricing and marketing strategies. For further exploration, consider experimenting with different goods and analyzing their relationships to deepen your understanding of demand elasticity.