Obsidian shows as result a yellow strip of LaTex code. I have installed the two available Obsidian plugins for MathJax and LaTeX environments but they couldn’t solve this issue.

Note: Obsidian renders simple equations like $$x^2 = b$$. So I don’t know what type of equations work and do not work in Obsidian.

I thought that space didn’t count in LaTeX. Nevertheless, why this only not renders in Obsidian?

But I don’t understand why this renders:

$$\begin{aligned}
a &=\text{Age index}\\
a_0 &=\text{Age of entrance into the labour force}
\end{aligned}$$

But this does not:

$$\begin{aligned}
a &=\text{Age index}\\
a_0 &=\text{Age of entrance into the labour force}\\
a_{RA} &=\text{Retirement age}\\
a_{max_c} &=\text{Maximum age/end of pension period of cohort \(c\)}\\
P_{c,a} &=\text{Pension payments to cohort \(c\) at age \(a\)}\\
r &=\text{internal rate of return}\\
C_{c,a} &=\text{Contribution payments by cohort \(c\) at age \(a\)}
\end{aligned}$$

Finally I (think) I found the solution for this puzzle.
If you have a previous text in LaTeX you have to paste it as text to Obsidian because some   will remain in your code and the preview can’t be created.