2.income and substitution effects are used to understand the effects of a price change.whatever the direction of the income effect,with only two goods the substitution effect is always negative.the pure relative price effect the consumer to substitute away form the good whose relative price has risen towards the good whose relative price has fallen.abstracting from income effects,goods are necessarily substitutes for one another in a two-good world
even with many goods,there is always a substitution effect away from goods whose relative price has risen.however,substitution may not be towards all other goods.consumers substitute away fromm goods consumed jointly with the good whose price has risen.
這個最好能有圖表,可是這里表示不出來~
3.substitution increase,demand decrease
income increse,demand increase
這個自己組織下語言