[填空题]
The number of users on a new social network i/ynk3 :yiia; fnxfw mdj7(9-vf 2018 was 320000. One year later, in 2019, the number of users on this network is (mxv-7jd 9ffwestimated to be 350000. The number of the users on this 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.
