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# final integration challenge for tonight... watch

1. Probably a walk in the park for you but giving me a headache!!!

A radioactive substance decays at a rate proportional to its mass. Express this as a differential equation where m is the mass of the substance present at time t.

I think it is something like dm/dt = -m - grateful for your thoughts.....
2. (Original post by mattj35)
Probably a walk in the park for you but giving me a headache!!!

A radioactive substance decays at a rate proportional to its mass. Express this as a differential equation where m is the mass of the substance present at time t.

I think it is something like dm/dt = -m - grateful for your thoughts.....
That looks right.
3. dm/dt = -km

Where k is a constant.

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