What is promotional elasticity in economics?

What does elasticity mean in economics? Please provide examples?

• Below are some terms that the professor mentioned. Can you please provide an explanation of what it means and provide an example. Perfectly inelastic Inelastic elasticity Elastic elasticity Perfectly elastic THANK YOU are there any other ones?

• Answer:

  Elasticity of demand measures the extent to which the quantity demanded of a commodity increases or decreases in response to in increase or decrease in any of its quantitative determinants. As you must be knowing, demand of a commodity depends on price, income of the consumer and price of related goods etc. Thus we have Price elasticity, Income elasticity and Cross elasticity of demand. Basically, if a change in price doesn't lead to much of a change in the demand of a commodity, it is called an Inelastic demand. And if the slightest change in price causes the demand to fall to zero, then its an Elastic demand. Perfectly Inelastic means a change is price causes no change in the quantity demanded. It also means that even substantial changes in price leaves the demand unaffected. This mainly applies to essential commodities, like for example: Salt. Perfectly Elastic refers to a situation when demand is infinite at the prevailing price. It means that even a small change in price causes the demand to fall to zero. There are no terms like Inelastic elasticity and Elastic elasticity in Economics. Elasticity and inelasticity of demand(and supply) depends on various factors. Similarly, say if your income rises then the demand for coarse grains will decrease. You will consume more of whole and good quality grains. Thus demand of coarse grain is elastic. There are other terms like, Unitary Elastic demand, Greater than Unitary elastic and Less than Unitary Elastic demand. This may help you more: http://en.wikipedia.org/wiki/Elasticity_%28economics%29