I found the error.
Oops. Silly me. I entered the data incorrectly into maple. should be , not .
The rest is fine.
The series
is a least squares Chebyshev polynomial approximation of f(x) on [-1,1], if
Find the quadratic least squares Chebyshev polynomial approximation of
, on .
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Their answer (I don't know where I went wrong):
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My working:
Let (to map to [-1,1] interval).
.
.
Then
So, (you can compute on Maple),
So
Then to map back to ,
.
Now, simplifying is optional, but this answer is not correct (apparently).
Any idea what I did wrong? Or is this the wrong forum for this stuff?