Determine the coordinates of the centroid of the parabolic spandrel bounded by the function $y(x) = b + kx^2$, and the positive $x$ and $y$ axes in terms of constants $a$ and $b$.
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Determine the coordinates of the centroid of the parabolic spandrel bounded by the function $y(x) = b + kx^2$, and the positive $x$ and $y$ axes in terms of constants $a$ and $b$.