Testing MathJax

Following the instructions here, MathJax works on Blogpost.
I typed

$\cos^2\theta-\sin^2\theta=\cos 2\theta$

and here's the result: \(\cos^2\theta-\sin^2\theta=\cos 2\theta\)
Antoher equation: \[ ax+\frac{b}{y}=1 \] This time, the equation is in display mode.
How about the inline verbatim environment? Googling "mathjax verbatim", we have \[\verb*$x^2\sqrt y$* \text{ yields } x^2\sqrt y\] on $\rm \TeX \text{ Commands available in MathJax}$ . Nevertheless, it only works in display mode.
Finally, let's get some equations numbered, just like an example on MathJax. \begin{equation} \int_{0}^{\frac{\pi}{2}} \sin x \, \mathrm d x = 1 \end{equation}