How to input an endmark in an environment different from the proof environment?

Question

I want to put an endmark in the solution environment, I tried

\documentclass{article}
\usepackage{amsthm}
\usepackage{amssymb,amsmath}
\newtheorem{mytheorem}{Theorem}[section]
\newtheorem{ex}{Example}[section]
\begin{document}
\section{Section one}
\begin{mytheorem}
If \(U\) or \(V\) then...

\begin{proof}[Proof]
The Proof
        \begin{equation*}
            Ax = b.
        \end{equation*}
\end{proof}
\end{mytheorem}

\begin{ex}
This is a example
\end{ex}
\begin{proof}[Solution]
\renewcommand{\qedsymbol}{\ensuremath{\diamondsuit}}
This is a solution
\end{proof}
\end{document}

How do I write a command in the preamble to put an endmark in the solution environment?

Answer 1

Use this

\newenvironment{mysol}{%
  \begin{proof}[Solution]}{%
  \renewcommand{\qedsymbol}{\ensuremath{\diamondsuit}}%
  \end{proof}%
}

Then you just write your solutions with the environment mysol.