test page2

def

\[ dddddddddddddddddddddddddddddddddddddddd \]

\[ \frac{\mathrm{d}a}{\mathrm{d}x}\frac{\mathrm{d}b}{\mathrm{d}a}\frac{\mathrm{d}y}{\mathrm{d}b}\frac{\mathrm{d}y}{\mathrm{d}y}
\leftarrow
\frac{\mathrm{d}b}{\mathrm{d}a}\frac{\mathrm{d}y}{\mathrm{d}b}\frac{\mathrm{d}y}{\mathrm{d}y}
\leftarrow
\frac{\mathrm{d}y}{\mathrm{d}b}\frac{\mathrm{d}y}{\mathrm{d}y}
\leftarrow \frac{\mathrm{d}y}{\mathrm{d}y} \]