Question 859111
Half life usually denotes using an equation with (1/2) as the base.
{{{A=A[0]*(1/2)^(kt)}}}
where 
{{{A[0]/2=A[0]*(1/2)^(2k)}}}
{{{1/2=(1/2)^(2k)}}}
so then {{{2k=1}}}
{{{k=1/2}}}
so,
{{{A=A[0]*(1/2)^(t/2)}}}