5. TikTok is a video-focused social networking service, launched in 2017. A marketing student found out that the number of TikTok users between 2017 and 2020 can be modelled by the function t) = 121.396.9054: U 5 t 5 4 where t) is measured in millions , with t = 0 corresponding to 2017. (a) What was the number of users in 2019? Round to the nearest whole. (b) What will be the number of users in 2023, assuming that the trend will continue? Round to the nearest whole.. Chapter 5 Section 4 11. Consider the equation ctytory = e (a) Find dy using implicit differentiation. (b) Find the slope of the tangent line to the graph of the given equation at the point (e - 1, 0)