<p>There is no general way of determining elasticity from graph, however linear demand function has a property where demand is infinitely elastic at the top and then elasticity monotonously decreases (in range where <span class="math-container">$p&gt;0$</span> and <span class="math-container">$q&gt;0$</span>) and is infinitely inelastic at the bottom.</p>
<p>Hence, in the case above you  can say that <span class="math-container">$\epsilon_1&gt; \epsilon_2 &gt; \epsilon_3$</span> (where epsilon denotes elasticity at point <span class="math-container">$i$</span>).</p>

CC BY-SA 4.0
2022-04-27T12:39:06.937Z
Thanks for the answer. I am a little bit confused how could we understand why `infinitely elastic at the top and then elasticity monotonously decreases`? I feel like the elaticity should be all the same on this linear graph since we only looks at percentages changes in quantity v.s percentage changes in price. What am I missing??? Thanks!
James
CC BY-SA 4.0
2022-04-27T13:34:25.113Z
@James elasticity for a general linear demand $D=a-bp$ is given by $\frac{-bp}{a-bp}$ you can plug different numbers into that equation for $p$ and keep parameters of demand $b$ -slope of demand curve and $a$ - y intercept of demand curve constant and you will see that elasticity of linear demand curve is different everywhere.
1muflon1
CC BY-SA 4.0
2022-04-27T10:12:00.887Z
2022-04-27T10:12:00.887Z
1muflon1
<p>Let's say I have a demand curve looks something like this:
<a href="https://i.sstatic.net/72Ul7.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/72Ul7.png" alt="enter image description here" /></a></p>
<p>How could I analyze who have the highest or lowest price elasticity of demand?</p>
<p>it seems that the point 1 has highest price or demand? But why? How does the graph tells us that information?</p>
<p>Any helps will be appreicate!</p>

<microeconomics><elasticity>
How to compare the price elasticity of demand from different points by looking at the graph?
James
# How to compare the price elasticity of demand from different points by looking at the graph?

(Asked by: username_0 on 2022-04-27)

Let's say I have a demand curve looks something like this:
[![enter image description here](https://i.sstatic.net/72Ul7.png)](https://i.sstatic.net/72Ul7.png)

How could I analyze who have the highest or lowest price elasticity of demand?

it seems that the point 1 has highest price or demand? But why? How does the graph tells us that information?

Any helps will be appreicate!

**Tags:** microeconomics, elasticity


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## 1 answers

### Answer by username_1 on 2022-04-27. Score: 1 | Accepted answer

There is no general way of determining elasticity from graph, however linear demand function has a property where demand is infinitely elastic at the top and then elasticity monotonously decreases (in range where $p>0$ and $q>0$) and is infinitely inelastic at the bottom.

Hence, in the case above you can say that $\epsilon\_1> \epsilon\_2 > \epsilon\_3$ (where epsilon denotes elasticity at point $i$).

> **Comments:**
> **username_0**: Thanks for the answer. I am a little bit confused how could we understand why `infinitely elastic at the top and then elasticity monotonously decreases`? I feel like the elaticity should be all the same on this linear graph since we only looks at percentages changes in quantity v.s percentage changes in price. What am I missing??? Thanks!  
> **username_1**: @username_0 elasticity for a general linear demand $D=a-bp$ is given by $\frac{-bp}{a-bp}$ you can plug different numbers into that equation for $p$ and keep parameters of demand $b$ -slope of demand curve and $a$ - y intercept of demand curve constant and you will see that elasticity of linear demand curve is different everywhere.  

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