Math Is Fun Forum

taylor_2009

Member

Registered: 2010-01-25

Posts: 28

Word problem set up help

Ecologists estimate that, when the population of a certain city is x thousand persons, the average level L of carbon monoxide in the air above the city will be L ppm (parts per million), where L=50+0.4x+0.0006x². The population of the city is estimated to be x=752+23t+0.5t² thousand persons t years from the present. Find the rate of change of carbon monoxide with respect to the population of the city, and the time rate of change of the population when t=2. How fast (with respect to time) is the carbon monoxide level changing at time t=2.

I don't even know where to begin. Can you explain what I need to do and how to set up the equation please?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Word problem set up help

Hi taylor_2009;

Find the rate of change of carbon monoxide with respect to the population of the city,

You want dL / dx for that one.

and the time rate of change of the population when t=2.

You will just plug in 2 into dx / dt.

Do you see what you need for the 3rd question?

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