When a certain drug is taken orally, the concentration of the drug in the patient's bloodstream after t minutes is given by
c(t) = 0.06t − 0.0002t2,
where 0 ≤ t ≤ 240 and the concentration is measured in mg/l.
when is the maximum serum concentration reached?

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

Proceed as in example 3 in section 6.1 to rewrite the given expression using a single power series whose general term involves xk. ∞ n(n − 1)cnxn − 2 n = 2 − 4 ∞ ncnxn n = 1 + ∞ cnxn n = 0

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?