Question

Nancy can you help me
Radium decreases at the rate of 0.0428 percent per year.
a. What is its half-life? (A half-life of a radioactive substance is defined to be the time needed for half of the material to dissipate.
b. Write a recurrence relation to describe the decay of radium, where rn is the amount of radium remaining after n years.

Answer 1

Read carefully...

http://books.google.com/books?id=Lq3Z34tj0XEC&pg=PA381&lpg=PA381&dq=Radium+decreases+at+the+rate+of+0.0428+percent+per+year.&source=bl&ots=gyde8oUJOg&sig=jAlWjNedjAw_CDmNHLzu_vX5VeY&hl=en&ei=VsDNTeCWCMe2twe94dT9DQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCkQ6AEwAw#v=onepage&q&f=false

Answer 2

THANKS!

Answer 3

;)

Answer 4

y = Ae^(-kt)

Answer 5

general formula for exponential decay

Answer 6

A/2=A(0.000428)^x
1/2=(0.000428)^x
find x

Answer 7

* correction
A/2=A(1-0.000428)^x

Answer 8

\[1/2=(1-0.000428)^x\]

Answer 9

\[\log _{0.999572}(.5)\]

Answer 10

ok

Answer 11

that's half life

Answer 12

so how does translate to what I need for b

Answer 13

\[r_n=r_{n-1}(0.999572)\]

Answer 14

are you electrical engineer or student?

Answer 15

student this is module for 1 credit and I'm struggling!

Answer 16

I was asking elecengineer

Answer 17

sorry

Answer 18

np

Answer 19

by the way, did you figure out that credit card problem?

Answer 20

Suppose that one started out with 2 grams of radium. Find a solution for the discrete dynamical system illustrating this process and give the value for r(100), the amount remaining after 100 years.

Answer 21

yes

Answer 22

Okay,
we can use above formula
=2(1-0.000428)^100

Answer 23

approximately 1.92

Answer 24

that make sense because its half life in 1619 years so in 100 years there is not much difference