1. parametric curve x = x(t), y = y(t) when t=2, x(2)=4, x'(2)=2, x"(2)=5, y(2)=2, y'(2)=2, y"(2)=1,find(X=4)=?

(13) A logistic population model with relative growth rate 0.1 per year and carrying capacity 50 thousand can be expressed by the differential equation =0.1P(1 - ), with P in thousands and t in years. Given that the initial population is 9 thousand. Find the population size after 20 years. (If you memorized the formula, then you need to derive it for this problem.)