Homework 8:
Due Monday 6/30/14
1. Revay throws a rock into a pond and it makes a circular ripple that is increasing in
size. The radius of the circle is increasing by 3 feet every second. Express the radius,
area, and circumference of the circle each as functions of time.
2. The domain of a function is all possible input values and the range is all possible
output values. If x is restricted to the closed interval from 1 to 4 (1 ≤ x ≤ 4), what is
the range of f (x) = 2x + 1. (Hint: This function is a line and the question is asking
what possible values can y be if x is between 1 and 4.)
3. If the range of f (x) = 2x is 20 ≤ x ≤ 100 what is the domain?
4. Suppose there is a town where the barber only cuts the hair of people who do not cut
it themselves. Also anyone who does not cut their own hair must get it cut by this
barber. Who cuts the barber’s hair?
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