This is LaTeX code:

[latex]
\displaystyle [\partial_r (f\circ \Phi), \partial_\varphi (f\circ \Phi), \partial_\psi (f\circ \Phi)]=
[\partial_x f, \partial_y f, \partial_z f] \cdot\frac{\partial(x,y,z)}{\partial(r,\varphi,\psi)}
[/latex]