$ \int\limits_{0}^{\infty} \frac{ dx }{(1+x^{\alpha})^{\alpha}} = 1 $ where $\alpha$ is the golden ratio

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If got this question from here: Find a number $\alpha > 1$ such that the following holds

I was wondering if something with my answer is wrong, as it still has a downvote.

Let $\alpha$ be the golden ratio, so ‎especially $\alpha=\frac{1}{\alpha-1}$ holds.

$\int\dfrac{dx}{(1+x^\alpha)^\alpha}=\int \dfrac{dx}{(1+x^\frac{1}{\alpha-1})^\alpha}=x(x^{\frac{1}{\alpha-1}}+1)^{1-\alpha}=x(x^\alpha+1)^{1-\alpha}$

So $\int^\infty_0\dfrac{dx}{(1+x^\alpha)^\alpha}=\lim_{x\rightarrow\infty} x(x^\alpha+1)^{1-\alpha}=\lim_{x\rightarrow\infty} \frac{x}{(x^\alpha+1)^\frac{1}{\alpha}}=1$