Elasticity of demand is a measure of the responsiveness of quantity demanded to a change in price. It is calculated as the percentage change in quantity demanded divided by the percentage change in price.


There are three types of elasticity of demand:

• Elastic demand: when the percentage change in quantity demanded is greater than the percentage change in price (Ed > 1)


• Inelastic demand: when the percentage change in quantity demanded is less than the percentage change in price (Ed < />


• Unitary demand: when the percentage change in quantity demanded is equal to the percentage change in price (Ed = 1)

To calculate the value of x for which elasticity of demand will be unity, we need to use the formula for elasticity of demand:
Ed = (% change in quantity demanded) / (% change in price)

If we assume that the demand function is given by Q = f(x), where x is the price of the good, then the percentage change in quantity demanded can be expressed as:
(% change in quantity demanded) = (change in quantity demanded) / (average quantity demanded) x 100%
= [(f(x + 1) - f(x)) / (0.5 x (f(x + 1) + f(x)))] x 100%

Similarly, the percentage change in price can be expressed as:
(% change in price) = (change in price) / (average price) x 100%
= [(x + 1 - x) / (0.5 x (x + 1 + x))] x 100%
= 100 / (x + 1)

Now, substituting these values in the formula for elasticity of demand, we get:
Ed = [(f(x + 1) - f(x)) / (0.5 x (f(x + 1) + f(x)))] / [100 / (x + 1)]

Simplifying this expression, we get:
Ed = [(x + 1) x (f(x + 1) - f(x))] / [100 x f(x)]


To find the value of x for which elasticity of demand will be unity, we need to solve the equation:
[(x + 1) x (f(x + 1) - f(x))] / [100 x f(x)] = 1

This equation is not easy to solve analytically, and requires numerical methods such as iteration or graphical analysis. However, in general, the value of x for unitary elasticity of demand will depend on the shape of the demand function f(x) and its slope at the point of interest.


In summary, unitary elasticity of demand occurs when the percentage change in quantity demanded is equal to the percentage change in price. The value of x for which elasticity of demand will be unity depends on the demand function and its slope, and can be found by solving the equation for elasticity of demand.

Let qx=1500/px the elasticity of demand of x when it's price falls from