Can Someone help me with this?

2. Originally Posted by lilwayne
Can Someone help me with this?
If the half life is 3.3 days and you have m = 880 mg at t = 0 then you will obviously have 440 mg when t = 3.3 ....

3. Originally Posted by mr fantastic
If the half life is 3.3 days and you have m = 880 mg at t = 0 then you will obviously have 440 mg when t = 3.3 ....
yeah i know that but i dont get what to fill in the blanks..

4. $\displaystyle 440 = 880e^{3.3k}$

solve for $\displaystyle k$ and finish the problem.

5. Originally Posted by skeeter
$\displaystyle 440 = 880e^{3.3k}$

solve for $\displaystyle k$ and finish the problem.
yeah i ended up doing that and what i got was 1/2 and 3.3 for the first 2 blanks.

2 and 3.3 for the second 2 blanks.

880, 2 and 3.3 for the last 3 blanks.

but it was wrong, what did i do wrong?

6. Originally Posted by lilwayne
yeah i ended up doing that and what i got was 1/2 and 3.3 for the first 2 blanks.

2 and 3.3 for the second 2 blanks.

880, 2 and 3.3 for the last 3 blanks.

but it was wrong, what did i do wrong?
you forgot to divide the right side by 880 ...

$\displaystyle 440 = 880e^{3.3k}$

divide both sides by 880 ...

$\displaystyle \displaystyle \frac{1}{2} = e^{3.3k}$

continue ...

7. yeah i did that, then i did ln1/2 = lne^3.3k

which is ln1/2 = 3.3k

and i was told that ln(1/2) = -ln(2)

so i had k = -ln(2)/3.3

is that right so far?

8. Nvm got it.

9. Originally Posted by lilwayne
Nvm got it.
you're welcome.