Help with dS/dt and dV/dt

ltolila

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PLEASE HELP ME IM SO LOST

1. A company finds that the sales of a particular product are declining by 12% per year. That is dS/dt= -.12S. If the current sales are 4000 units per year, find how long it will take for the sales to be half the current amount?

2. The Center for Disease control has found that a virus is spreading at a rate of 4.3% per year. That is dV/dt= .043V. If there are currently 12,000 people infected by the virus, how long will it take to have 50,000 people infected?
 
PLEASE HELP ME IM SO LOST

1. A company finds that the sales of a particular product are declining by 12% per year. That is dS/dt= -.12S. If the current sales are 4000 units per year, find how long it will take for the sales to be half the current amount?

So dS= -.12S dt, \(\displaystyle \dfrac{dS}{S}= -.12 dt\). Can you integrate those?


2. The Center for Disease control has found that a virus is spreading at a rate of 4.3% per year. That is dV/dt= .043V. If there are currently 12,000 people infected by the virus, how long will it take to have 50,000 people infected?
So dV= 0.43Vdt, \(\displaystyle \dfrac{dV}{V}= 0.43t\).
 

So dS= -.12S dt, \(\displaystyle \dfrac{dS}{S}= -.12 dt\). Can you integrate those?



So dV= 0.43Vdt, \(\displaystyle \dfrac{dV}{V}= 0.43t\).

I dont understand what you mean by integrate them? I don't really know what the dS/dt stands for..
 
Then you need to talk to your teacher. If you are taking Calculus, are expected to do problems like these, and don't know what "dS/dt" means, you have a serious problem.
 
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