I am reading solution to this problem and I have questions.
In the fix point function in the problem is:
$g(x) = (3x^2 + 3)^\frac{1}{4}$ and where x $\in$ [1,2]
And g prime is in the image I linked to.
My question is why is $k = 6^{-.5}$
That is, where does it come from?