[填空题]
The number of users a;hus(hv ii++on a new s,d njx 8 zg +tk)g.dznq,jyr:134j crgocial network in 2018 was 320000. One year later, in 2019, the number of users on this network is estimated to be 350000. The number of the users on cd. j,4:g+ rg),8xtd gyj1znkr jn3qzthis network, N, can be modelled by the function
N(t)=320000$\times$$b^t$,t≥0,where t is the number of years since 2018 and b is a constant.
1.Find the value of b. b ≈
2.Estimate the number of the users on this network there will be in 2023. N ≈ users
3.Forecast the year for which the number of the social network users reaches one million. Give your answer correct to the nearest year.
