Problem set 3 Due: Tuesday October 13, 1998
Curve-fitting and Interpolation
1.
(a)
Take x i = 1,2,3, ... 10 , generate 10 corresponding
random y i 's using Matlab's randn function.
Fit both a straight line and a parabola to your data. Plot the results.
(b) Fit the polynomial of highest order possible to your data.
Plot the polynomial on a finer grid (i.e. more x 's between
1 and 10), highlighting the data points. Compare that high order polynomial
to the spline interpolant which you can obtain using matlab's spline
function.
(c) repeat (b) for 15 x's from 1 to 15 and 15 corresponding y's.
(d) what do you conclude from your experiments in (b) and (c) (plus
whatever other experiment you feel like doing)? Keep it brief but meaningful.
2.
Explain how you can use Matlab's polyfit to fit data to
an exponential decay law (such as radioactive decay data)
y = A e - B t . What are the best
A and B for this data?
Fabian Waleffe
1998-10-04