Hints for Assignment 4:

Problem 1, 2: How to plot zero contours of two functions f₁, f₂ together:
```
ezplot('x1-sin(x1+x2)',[0 2 0 2])
setcurves('linestyle','--')  % make all curves dashed 
hold on
ezplot('x2-cos(x1-x2)',[0 2 0 2])
hold off
```
You have to download setcurves.m first and put it in a directory where Matlab can find it. You can also use e.g. setcurves('color','red').
Problem 1, 2: For the Newton method iterate until || x^(k) - x^(k-1) || <= 10^-12 .
Problem 1, 2: You only need one plot which shows both the contours and the marks for the computed solutions. Use plot(x(1),x(2),'o') to mark the computed solutions.
Problem 3: Remember to take the logarithms (log in Matlab) of the population values before doing the least squares fit !!
Print out the vector c which you get for (i),(ii),(iii) and check that they are the same (up to roundoff errors). Then use one of those c vectors for the plot and for the predicted population.
Problem 4: Download co2.dat. Then use in Matlab load co2.dat (not load co2 as stated in the problem)