Question

How do I write a half life function?

Answer 1

takes awhile :)

Answer 2

all thats really needed is to find the rate ....

2P = P e^(rt) .... solve for r

Answer 3

how do i do this? i have this info, but i dont know how to find the half life function. F(x)=45e^-.89x
y=45e^-.89x
y/45 = e^(-.89x)
in y/45 = In e^(-.89x)
in y - in 45 = in e^-.89x
in y = in e^-.89x+3.81
in y = -.89x+3.81

Answer 4

It says it should look like this: F(x)=A(1/2)^x. Where A is the initial amount of the substance and x represents the time for decay

Answer 5

its asking for the half life time? or is it asking to write up a function to determine the halflife?

Answer 6

F(x) = 45e^-.89x

y = 45e^-.89x

y/45 = e^-.89x

lny -ln45 = -.89x

-(lny -ln45)/.89 = x

such that y=45/2

Answer 7

it´s telling me to write a half life function

Answer 8

would that be it y=45/2?

Answer 9

ok, i had to review something first :) i see it now

Answer 10

you had the initial setup going good, lets call x, t for time tho

45/2 = 45e^-.89t

1/2 = e^-.89t

-ln(2) = -.89t

ln(2)/.89 = abt 0.78

y = 45*(1/2)^(x/.78) seems to be right then

Answer 11

that´s it?

Answer 12

as far as i can tell, yes :)

Answer 13

1/2 = e^-.89t , from this point we can begin to determine a replacement
for the e^() stuff

1/2^(1/t) = e^-.89

and the rest of the workings gives us a solution for t

-ln(2) = -.89t

ln(2)/.89 = abt 0.78 = t

Answer 14

replacing equal parts we get

y = 45 e^(-.89x)

y = 45 (1/2)^(1/.78)^x

y = 45 (1/2)^(x/.78)