
Joaquin B. answered 11/09/20
Chemical Engineer with 10+ years teaching/tutoring Calculus
Given S(t) = t2e - 0.1t (Note this is based on the question you wrote down, the function may be incorrect based on your notation).
The first and second derivatives are S'(t) = 2et - 0.1 and S"(t) = 2e, respectively.
To find critical points set S'(t) = 0, this leads to the equation: 0 = 2et - 0.1, solving for t yields t = 0.1/(2e). Since the second derivative is constant at a value of 2e (which is greater than 0), the critical value is a minimum.
There are no inflection points in the function given and the concavity is always up, which makes absolutely no sense since this problem refers to the amount of medication in the bloodstream at any time t after medication is administered. This medicine is showing a negative concentration in blood and then it is increasing to infinity as time goes to infinity. The function is non-sensical since most medication is metabolized and slowly disappears from your bloodstream.