[填空题]
The concentration in mg of a6yy7vaqjyk zflhs5p( cx , ;00 certaif3x- wtvq wd+g+nwd-78k8h 5;-oqz yuogdp u)n medicine t hours after administration can be modgnx pod7+z8q )wyf tku -;8d5-wq-3uwg hvdo+eled by C(t) = 1000te$^{-1.25t}$ , t≥0.
1.Find the rate of change of the concentration with respect to time.
C'(t) = 1000e$^{-1.25t}(a-b1.25t)$ , a= , b= .
2.Find the value of t when the rate of change of C is zero.
t= .
3.Determine if the time found in part (b) is a local minima or maxima for C. Justify your answer.
