Question

How do you find the slope of a demand curve ?

Answer 1

Hint : Slope is represented by ‘ m ’ . The slope can be calculated by finding the ratio of the “ vertical change ” we say graphically as the y-axis denoted by $\vartriangle y$ = ${y_2} - {y_1}$ , to the “ horizontal change “ we say graphically as the x-axis denoted by $\vartriangle x$ = ${x_2} - {x_1}$ , between the two different points on a same line . The formula of slope is $m = \dfrac{{{y_2} - {y_1}}}{{{x_2} - {x_1}}}.$ The demand curve is a graphical representation of the relationship between the price of a good or service and the quantity demanded for a given period of time . The price is drawn along the y-axis and the quantity demanded on the x-axis .

Complete step-by-step answer :
It is very easy to find the slope of a demand curve if you know the concept of basic slope . As per finding the slope , we must divide the rise by run .
If we talk about a demand curve then that means there will be a ratio of the change in price ( that is $\vartriangle y$ = ${y_2} - {y_1}$ ) to the change in quantity demanded ( $\vartriangle x$ = ${x_2} - {x_1}$ ) .
Let's consider change in price as $\vartriangle P$ = ${P_2} - {P_1}$ .
Let's assume the change in quantity demanded as $\vartriangle Q$ = ${Q_2} - {Q_1}$ .
Slope of Demand Curve = $\dfrac{{{P_2} - {P_1}}}{{{Q_2} - {Q_1}}}$ = $\dfrac{{\vartriangle P}}{{\vartriangle Q}}$ .
Hence , by this you can find the slope of a demand curve .
So, the correct answer is “ $\dfrac{{{P_2} - {P_1}}}{{{Q_2} - {Q_1}}}$ = $\dfrac{{\vartriangle P}}{{\vartriangle Q}}$ .”.

Note : In order to find this slope , we need to take two different points but it has to be on the demand curve .
The ratio of ordered pairs must be fulfilled .
Remember that this phenomenon works only when there will be a linear demand curve .
Need to learn derivatives , as the slope is the derivative at the specific quantity value.