因为幂函数的定义域为[0，+∞），且幂函数在定义域上单调递增，
所以y≥0，即函数的值域为[0，+∞）．
故答案为：[0，+∞）．
某公司是一家新建企业，为了在市场竞争中求得生存及长远发展，决定从一开始就采用国家标准或国际标准，规范企业管理，打好管理基础。新厂建成后欲生产甲、乙、丙三种产品，经调查，甲产品现已有推荐性行业标准，乙产品已有推荐性国家标准，丙产品目前尚无相应的国家标准、行业标准和地方标准。
该厂制定丙产品的企业标准，则应( )。
A．由企业法人代表批准、发布，由其授权的部门统一管理
B．是在企业内协调、统一的产品技术要求
C．报当地工商管理部门备案
D．报当地标准化行政主管部门备案
Ali is a dealer in Persian rugs. As his business has been rather slow, he placed an advertisement in the Saturday edition of his local paper stating:‘Once in a lifetime opportunity to own a handmade Persian antique rug for only ￡1,500 – cash only. This is a serious offer – the rug will go to the first person who accepts it – offer valid for one day only – today Saturday.’When Bud saw the advert, he immediately posted a letter of acceptance of Ali’s offer in order to make sure he got the rug.Cil also saw the advert and after inspecting the rug offered Ali a cheque for ￡1,500, but he refused to accept the cheque and told her she could not have the rug.Later in the day, Das asked Ali if he would keep the offer open until he could get to his bank to arrange a loan. Ali agreed, but subsequently, when Ed offered to pay ￡2,000 in cash for the rug, Ali sold the rug to him.On Monday morning Bud’s letter arrived, and Das returned to complete his purchase of the rug.Required:In the context of the rules governing the creation of contracts, advise:
(b) whether Bud has entered into a binding contract with Ali; (2 marks)
