PHYS 27/193: Homework 6

Type your numerical answers in a text file, save it as NAMEhw6.txt, along with PDF plots,
and email them to me as attachments (if you like you can tar them together in one tar file).

1. Using your "CalPop.dat" file, fit the US Population data to a cubic function: f(x) = a3*x**3 + a2*x**2 + a1*x + a0.
   Find a3, a2, a1 and a0. Report the values in your "NAMEhw6.txt" file.
   • Plot the data along with your fit function.
   • Make a PDF copy of this plot called "NAMEUSpopfit.pdf".
2. Predict the US population in 2050, and in 2100?

3. Do the same for the California population.

   Note that if you want to fit to data in columns 1 and 3, you can put a "using" after the "filename" in a fit command, the same way you do when using "u..." (using) in a plot command.
   For example: fit f(x) "CalPop.dat" u 1:3 via...

4. Plot the ratio of CA population to US population vs. year, by employing the using command.
   Save a PDF called "NAMEpopratio.pdf"

5. Fit this ratio to a line. What is the slope of this line?
   Save a PDF of this called "NAMElinefit.pdf".

6. In what year will the CA/US fraction of US population be 15% at current growth rates? When will the CA/US fraction be 1/4?

Go to this page to see a worked example using the freefall data you made in homework 4.