Solve this:
Q.18. If $A=\frac{1}{\mathrm{\pi }}\left[\begin{array}{cc}{\sin }^{-1}\left(\mathrm{\pi x}\right)& {\tan }^{-1}\left(\frac{x}{\mathrm{\pi }}\right)\\ {\sin }^{-1}\left(\frac{x}{\mathrm{\pi }}\right)& co{t}^{-1}\left(\mathrm{\pi x}\right)\end{array}\right] and B=\frac{1}{\mathrm{\pi }}\left[\begin{array}{cc}-{\cos }^{-1}\left(\mathrm{\pi x}\right)& {\tan }^{-1}\left(\frac{x}{\mathrm{\pi }}\right)\\ {\sin }^{-1}\left(\frac{x}{\mathrm{\pi }}\right)& -{\tan }^{-1}\left(\mathrm{\pi x}\right)\end{array}\right]$, then find the value of A - B.