User:Salix alba

I'm Salix alba on wikipedia.

A rotation matrix in block style $$\begin{pmatrix} \cos \theta & -\sin \theta \\ \sin \theta & \cos \theta \end{pmatrix}$$ is the rotation matrix a reflection is in : style
 * $$\begin{pmatrix}

\cos 2 \theta & \sin 2 \theta \\ -\sin 2 \theta & \cos 2 \theta \end{pmatrix}$$ which is nice. A display eqn

$$\begin{pmatrix} a & b \\ c & d \end{pmatrix}$$

with no preceeding newline $$\int x \mathbf{d}x$$foo now add a new line

$$\int y \mathbf{d} y$$foo.