Find the function of the form
f(t) = c0 + c1sin(t) + c2cos(t)
+ c3sin(2t) + c4cos(2t)
that best fits the data points (0,0), (0.5,0.5), (1,1),
(1.5,1.5), (2,2), (2.5,2.5), (3,3), using least squares. Sketch the
solution, together with the function g(t) = t.