Writing subscript in Mathjax? - mathjax

Question

I want to type this .
I have tried like this
$$\lambda=\frac{0.693}{t_\frac{1}{2}}$$
Also,
$$\lambda=\frac{0.693}{{t}_\frac{1}{2}}$$
Also,
$$\lambda=\frac{0.693}{t_{\frac{1}{2}}}$$
But it don't work it display something like this
This code
also gives something that we don't want
Mathjax Configuration
<div class="layout"><script type="text/x-mathjax-config">
MathJax.Hub.Config({
TeX: {extensions: ["AMSmath.js","AMSsymbols.js","mhchem.js","noErrors.js","noUndefined.js"]},
tex2jax: {
inlineMath: [ ['$','$'], ["\\(","\\)"] ],
displayMath: [ ['$$','$$'], ["\\[","\\]"] ],
processEscapes: true
},
});
</script>
<script src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML"></script>
Browser= Google Chrome
OS= Windows 8.1

Answer 1

Use _{}
_{YOUR EXPRESSION}
Example:
$$Y_n = Y_{n-1}+{{(d/n)}sin(θ\pm n*Δ)}.$$
Result:

Answer 2

$$\frac{1}{\lambda}=\frac{0.693}{t_\frac{1}{2}}$$
renders exactly what you are asking for and I tested it already.
Note the difference:
I just copied your first mathjax code:
$$\lambda=\frac{0.693}{t_\frac{1}{2}}$$
Note that before the '=' on the left side of the equation you just and simply wrote \lambda and that was your only mistake, so I simply replaced \lambda with \frac{1}{\lambda} and that's all.
You already showed us in your question that you already know that underscore _ renders subscript text and symbols in mathjax by the way.

Answer 3

See the live example below:
window.MathJax = {
config: ["MMLorHTML.js"],
jax: ["input/TeX", "input/MathML", "input/AsciiMath", "output/HTML-CSS", "output/NativeMML"],
extensions: ["tex2jax.js", "mml2jax.js", "asciimath2jax.js", "MathMenu.js", "MathZoom.js"],
asciimath2jax: {
delimiters: [
['`', '`'],
['$', '$']
]
},
TeX: {
extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js", "noUndefined.js"]
},
tex2jax: {
inlineMath: [
['$', '$'],
["\\(", "\\)"]
],
processEscapes: true
}
};
.MathJax_CHTML {
font-size: 30px !important;
}
<script type="text/javascript" async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.4/MathJax.js?config=TeX-MML-AM_CHTML">
</script>
<p> $$\frac{1}{\lambda}=\frac{0.693}{t_\frac{1}{2}}$$</p>
<p> $$\frac{1}{\lambda}=\frac{0.693}{{t}_\frac{1}{2}}$$</p>
<p> $$\frac{1}{\lambda}=\frac{0.693}{t_{\frac{1}{2}}}$$</p>