On this question: Interpret the conditional density $f(x\mid\theta)$, where $\theta$ is the parameter of the density.? I had reformatted the question. The OP asked in a comment how he can learn LaTeX. I usually just give reference to the two meta threads that has some help:
MathJax basic tutorial and quick reference
Do we have an equation editing HOWTO?
but I also said that he could use the "sandbox" to test things (play around).
Right now, the sandbox is for
Sandbox drafts of long, complex answers.
I suggest that wording iis changed to that it allows (and encourages) use of the answers to learn LaTeX/MathJax as well. We could change the title to
Sandbox for drafts of questions and answers
The begining paragraph now reads:
This sandbox is intended for saving drafts of long, complex answers, especially answers whose composition takes a long time. It serves to localize to one thread the front-page "bumps" caused by edits to drafts of such answers, so that they may be easily ignored. Also, it helps to guard against losing longly-composed answers due to system crashes.
I suggest changing this to
This sandbox is intended for drafts of questions and answers, especially answers whose composition takes a long time. It is encouraged that people new to LaTeX and MathJax, use one of the answers here to test how it works. It also serves to localize to one thread the front-page "bumps" caused by edits to drafts of such answers, so that they may be easily ignored. Also, it helps to guard against losing longly-composed answers due to system crashes.
I welcome other suggestions below.