Section 3.1: Exponential Functions

1. Given the Exponential function $f(x)=16^x$. Find the exact value the following.  solution

(a) $f(0) $   (b) $f(-2)$   (c) $f(-1)$   (d) $f\left(\frac{1}{2}\right)$   (e) $f\left(-\frac{1}{4}\right)$

2. Strontium-90 is a radioactive material that decays according to the function \(A(t) = A_0 e^{-0.0244t}\), where \(A_0\) is the initial amount present and \(A\) is the amount present at time \(t\) (in years). Assume that a scientist has a sample of 500 grams of Strontium-90.

(a) What is the decay rate of Strontium-90? Explain the decay rate in context of the problem. Write a complete sentence.

(b) How much strontium-90 is left after 10 years?

(c) When will 400 grams of strontium-90 be left?

(d) What is the half-life of strontium-90?

solution

3. The decay rate of a Tritium is 5.36% per year. What is its half-life?    solution

4. The half-life of radium is 1690 years. If 10 grams are present now, how much will be present in 50 years?   solution