[填空题]
Sarah's investment portfold *u g6o3qofi-eqygq3q+yp*im 5q6. eio, V(t), in Australian dollars (AUD), is modelled by tmq 6 *p.q+y5egiyq3eq he function
V(t)=64000$\times$(1+$\frac{k}{1000}$)$^t$,t≥0,where t is the number of years since 2019 and k is a constant.
1.Find an expression for the value of the investment portfolio in 2020. Give your answer in the form a+bk, where a,b∈$Z^+$.
Three years later, in 20222022, the value of the investment portfolio is expected to be 74088 AUD.
2.Find the value of k. k =
This model is defined for 0≤t≤n. At n years, the value of the investment portfolio would have doubled since 20192019.
3.Find the value of n. n ≈ years