Determinants and elasticities of demand GapFill

In the short run, demand elasticity will be   elasticinelasticunitaryzero and becomes more  elasticperfectly elasticunitaryinelastic in the long run. Necessities such as water, housing, etc. tend to have elasticity of demand that is  inelasticperfectly elasticelasticunitary. In respect to price elasticity of demand (PED), the value of elasticity must always have a  highpositivenegativelow sign because of the inverse relationship between price and quantity on the demand curve. Normal goods and inferior goods must have  highpositivenegativelow and  highnegativepositiveelastic relationships respectively. Goods that are jointly demanded have  a negativea positivea crossan income price elasticity of demand that is  positiveunitaryperfectly elasticnegative. When a change in price yields the same proportionate change in quantity demand then its PED will be  unitaryelasticzeroperfectly elastic.