Question 857775
{{{A=Ie^(-kt)}}}, I is initial amount, A is final amount after time t.


FIND k
{{{ln(A)=ln(I)-kt}}}
{{{-kt=ln(A)-ln(I)}}}
{{{k=(1/t)(ln(I)-ln(A))}}}
{{{k=(1/t)ln(I/A)}}}
{{{k=(1/7)ln(75/0.009)}}}
{{{highlight(k=1.29)}}}


USE k TO FIND HALF-LIFE
Decay equation is {{{highlight_green(A=Ie^(-1.29t))}}}.
Let A=1/2 and let I=1.
Solve for t.