6. Demand Own-price changes Price offer curve(价格提供曲线) Ordinary demand curve Inverse demand curve(反需求函数) Income changes Income offer curve(收入提供曲线) Engel curve(恩格尔曲线 Cross-price effects6. Demand Own-price changes – Price offer curve （价格提供曲线） – Ordinary demand curve – Inverse demand curve （反需求函数） Income changes – Income offer curve （收入提供曲线） – Engel curve （恩格尔曲线） Cross-price effects