How to force a space in tilde vector?

Question

Following the question in How to use tilde

I want to have space between tilde. i tried used \space but not effect.

for example:

$\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2, \space\widetilde{x_1}^2, \space\widetilde{x_2}, ..., 1}$

$\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2,\space\widetilde{x_1}^2,\space\widetilde{x_2}^2, ..., 1}$

Full MWE

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{accents}

\begin{document}

% $ \| \underaccent{\tilde}{\tilde{x}} \| $

% This is my $\|\undertilde{\widetilde{x}}\|$

$\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2, \space\widetilde{x_1}^2, \space\widetilde{x_2}, ..., 1}$

$\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2,\space\widetilde{x_1}^2,\space\widetilde{x_2}^2, ..., 1}$


\end{document}

Answer 1

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{accents}

\begin{document}

    % $ \| \underaccent{\tilde}{\tilde{x}} \| $

    % This is my $\|\undertilde{\widetilde{x}}\|$

    $\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2, \,\widetilde{x_1}^2, \,\widetilde{x_2}, \cdots, 1}$

    $\hat{\undertilde{\widetilde{x}}}$ $=$ $\sqrt{0^2,\,\widetilde{x_1}^2,\,\widetilde{x_2}^2, \cdots, 1}$


\end{document}