College Algebra Formulas
please help with this college algebra decay problem?
Carbon-10 is a radioactive isotope with a half life of 19.255 seconds. Suppose you start with 1 gram of carbon-10. Then the amount f(t) of carbon-10 left after t seconds is .
it says to use the formula f(t)=2^at
Radioactive decays are modeled by exponential functions, and are usually expressed as f(t) = Ce^-rt
Since you want the answer as a power of 2, we’ll go that way:
Since f(19.255) = 0.5
0.5 = 2^(a*19.255)
2^a = 0.9646
=> a = -0.0514
f(t) = 2^(-0.0514t)
Harriel’s College Algebra, Section 2.1
