24. 已知等差数列{an}\{a_{n}\}{an}中满足a1=1a_{1}=1a1=1,a3=a22−4{a_3}=a_2^2-4a3=a22−4, (1)求通项公式ana_{n}an; (2)试求数列{an}\{a_{n}\}{an}中的最大项与最小项.