# Demand with Constant Price Elasticity

This diagram shows a demand curve with a constant elasticity of {{ model.elasticity | number:2}}, passing through point A.

Drag the price up and down to see how the quantity demanded changes,
and to see how the elasticity calculations change (and don't!) as you move along the demand curve.

What happens to the diagram when you drag point A around? When you change the elasticity using the slider?

{{error}}

elasticity

|\epsilon_{Q^D,P}| = {{ params.elasticity | number:2 }}
P = {{ params.price }}

Q^D(P) = {{ model.quantityAtPrice(params.price) | number:2 }}

\frac{\Delta Q^D}{\Delta P} = {{ model.inverseSlopeAtPrice(params.price) | number:2 }}

\epsilon_{Q^D,P} = \color{ {{ color('green') }} }{ \frac{dQ^D}{dP} } \times \frac{P}{\color{ {{color('demand')}} }{Q^D(P)}} || = \color{ {{ color('green') }} }{ {{ model.inverseSlopeAtPrice(params.price) | number:2 }} } \times \frac{ {{ params.price | number:0 }} }{ \color{ {{color('demand')}} }{ {{ model.quantityAtPrice(params.price) | number:2 }} } }|| = {{ model.elasticity | number: 2 }}
Copyright (c) Christopher Makler / econgraphs.org