i finished about all of this math problem except for the ending.

i reduced the problem to 5000^-10k

what i need is how to find the value of k

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- Jun 12th 2007, 09:26 PMchinese_man_77simple problem
i finished about all of this math problem except for the ending.

i reduced the problem to 5000^-10k

what i need is how to find the value of k - Jun 12th 2007, 09:27 PMJhevon
- Jun 12th 2007, 09:31 PMchinese_man_77
A = (ax)(10)^-kt

ax = 500

t= 10

A = 450

i got it down to 450 = 5000^-10k - Jun 12th 2007, 09:31 PMqbkr21Re:
RE:

Even if you set this equation equal to zero there still isn't a solution...

-qbkr21 - Jun 12th 2007, 09:33 PMchinese_man_77
its a regents question, so im pretty sure there is a solution and why would it be equal to 0 when its equal to 450

- Jun 12th 2007, 09:37 PMchinese_man_77
A = (ax)(10)^-kt

ax = 500

t= 10

A = 450

i got it down to 450 = 5000^-10k

i just dont know how to finish off the problem - Jun 12th 2007, 09:37 PMJhevon

we have $\displaystyle 450 = 500 \cdot 10^{-10k}$

$\displaystyle \Rightarrow \frac {450}{500} = 10^{-10k}$

$\displaystyle \Rightarrow \log \left( \frac {9}{10} \right) = -10k$ ........do you understand this step?

$\displaystyle \Rightarrow k = \frac {\log \left( \frac {9}{10} \right)}{-10}$ - Jun 12th 2007, 09:38 PMchinese_man_77
nice, thanks a lot

- Jun 12th 2007, 09:40 PMchinese_man_77
- Jun 12th 2007, 09:50 PMJhevon