Actinium is a radioactive soft metal that glows light blue in the dark. The isotope actinium-228 has a half-life of about 21.77 years. Suppose a laboratory worked with a 1.65 milligram sample of actinium-228. What function could be used to represent the amount, A
, in milligrams of the actinium-228 sample after t
years?(1 point)
Responses
A(t)=12(1.65)t21.77
cap a left parenthesis t right parenthesis equals one half left parenthesis 1.65 right parenthesis Superscript StartFraction t over 21.77 EndFraction
A(t)=1.65(12)t21.77
cap a left parenthesis t right parenthesis equals 1.65 left parenthesis one half right parenthesis Superscript StartFraction t over 21.77 EndFraction
A(t)=1.65(21.77)t2
cap a left parenthesis t right parenthesis equals 1.65 left parenthesis 21.77 right parenthesis Superscript StartFraction t over 2 EndFraction
A(t)=21.77(12)1.65t