Analyze graphs in order to classify elasticity as constant unitary, infinite, or zeroDescribe the price effect and also the quantity effectAnalyze exactly how price elasticities influence revenue and expenditure

In subject 4.1, we introduced the concept of elasticity and also how to calculate it, but we didn’t define why it is useful. Recall that elasticity measures responsiveness of one change to changes in another variable. If you own a coffee shop and wanted to boost your prices, this ‘responsiveness’ is miscellaneous you should consider. As soon as you increase prices, you recognize quantity will fall, however by just how much?

Elasticities can be divided into three large categories: elastic, inelastic, and unitary. An elastic demand is one in i beg your pardon the elasticity is higher than one, denote a high responsiveness to changes in price. Elasticities the are less than one indicate low responsiveness to price changes and also correspond to inelastic demand.

You are watching: Consider the demand curve illustrated in the figure to the right. is demand elastic or inelastic?

 Unitary elasticities indicate proportional responsiveness of either demand or supply, as summarized in the following table:

If . . .Then . . .And the Is referred to as . . .
\%\;change\;in\;quantity > \%\;change\;in\;price\frac\%\;change\;in\;quantity\%\;change\;in\;price) > 1Elastic
\%\;change\;in\;quantity = \%\;change\;in\;price\frac\%\;change\;in\;quantity\%\;change\;in\;price) = 1Unit Elastic

If we were to calculation elasticity at every allude on a demand curve, we can divide it into these elastic, unit elastic, and inelastic areas, as presented in figure 4.2a. This means the impact of a price change will count on whereby we room producing. Feel totally free to calculation the elasticity in any kind of of the regions, you will find that it indeed fits the description.

Figure 4.2a

To demonstrate, we have actually calculated the elasticities in ~ a suggest in every of the zones:

Point A = \frac\Delta Q\Delta P\cdot \fracPQ=\frac96.75\cdot \frac4.53=2Elastic

Point B = \frac\Delta Q\Delta P\cdot \fracPQ=\frac96.75\cdot \frac35=0.8Inelastic

Point C = \frac\Delta Q\Delta P\cdot \fracPQ=\frac96.75\cdot \frac3.3754.5=1Unit Elastic

In reality, the only point we require to find to recognize which locations are elastic and also inelastic is our suggest where elasticity is 1, or suggest C. This isn’t as hard as it might seem. Because our formula is equal to the station of ours slope multiply by a suggest on the graph, that will just equal 1 as soon as our suggest is equal to the steep of our graph. For a direct graph, this just occurs at the middle point, i beg your pardon is (4.5, 3.325) in this case.

Why is This Useful?

When Starbucks runs a purchase one get one totally free promotion, they efficiently lower the price that a drink by 50%. The firm sells more drinks, yet at a lower price. Elasticity determines whether or no this promotion will be profitable. That course, promotions are not constantly intended come be lucrative in the quick term. Oftentimes, that company will reduced prices to rise awareness the their brand-new products, together Starbucks does with its vacation drinks. (Credit: Starbucks)

So far, we have identified how to calculate elasticity at and between various points, however why is this expertise useful?

Consider a coffee shop owner considering a price hike. The owner has two things to account for when deciding even if it is to progressive the price, one that rises revenue and one the decreases it. Elasticity helps us identify which effect is greater. Referring earlier to our table:

When you rise price, you rise revenue on systems sold (The Price Effect).When you increase price, you sell fewer units (The quantity Effect).

These two results work against each-other. To recognize which outweighs the various other we deserve to look in ~ elasticity:

When our point is elastic our \%\;change\;in\;quantity > \%\;change\;in\;price definition if we rise price, our amount effect outweighs the price effect, causing a diminish in revenue. 

When our point is inelastic our \%\;change\;in\;quantity

Figure 4.2b

The first thing to keep in mind is the revenue is maximized in ~ the allude where elasticity is unit elastic. Why? If you are the coffee shop owner, girlfriend will notice that there room untapped methods when demand is elastic or inelastic.

If elastic: The quantity effect outweighs the price effect, definition if us decrease prices, the revenue gained from the more units sold will outweigh the revenue lost from the to decrease in price.

If inelastic: The price effect outweighs the quantity effect, an interpretation if us increase prices, the revenue gained from the higher price will certainly outweigh the revenue shed from much less units sold.

The results of price increase and decrease at different points space summarized in figure 4.2c.

Figure 4.2c

What around Expenditure

You will notification that expenditure is stated whenever revenue is. This is due to the fact that a dollar deserve by the coffee shop synchronizes to a dollar spent by the consumer. Therefore, if the this firm revenue is rising, climate the consumer’s expenditure is increasing as well. You should understand how to answer questions from both sides.


Elasticity is offered to measure up the responsiveness that one variable to another. This responsiveness can it is in labelled as elastic (e > 1), unit elastic (e = 1), and also inelastic (e Elasticwhen the elasticity is greater than one, indicating that a 1 percent rise in price will an outcome in a more than 1 percent boost in quantity; this indicates a high responsiveness come price.

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Inelasticwhen the elasticity is much less than one, indicating that a 1 percent boost in price paid to the for sure will result in a much less than 1 percent increase in quantity; this suggests a short responsiveness come price.Unitary elasticwhen the calculate elasticity is equal to one indicating the a adjust in the price of the great or organization results in a proportional adjust in the amount demanded or supplied