b
(b) $\frac{{{d^n}}}{{d{x^n}}}[\Delta (x)] = \left| {\begin{array}{*{20}{c}}{\frac{{{d^n}}}{{d{x^n}}}{x^n}}&{\frac{{{d^n}}}{{d{x^n}}}\sin x}&{\frac{{{d^n}}}{{d{x^n}}}\cos x}\\{n!}&{\sin \left( {\frac{{n\pi }}{2}} \right)}&{\cos \left( {\frac{{n\pi }}{2}} \right)}\\a&{{a^2}}&{{a^3}}\end{array}} \right|$
$ = \left| {\,\,\begin{array}{*{20}{c}}{n!}&{\sin \left( {x + \frac{{n\pi }}{2}} \right)}&{\cos \left( {x + \frac{{n\pi }}{2}} \right)}\\{n!}&{\sin \left( {\frac{{n\pi }}{2}} \right)}&{\cos \left( {\frac{{n\pi }}{2}} \right)}\\a&{{a^2}}&{{a^3}}\end{array}\,} \right|$
$ \Rightarrow $ ${[{\Delta ^n}(x)]_{x = 0}} = \left| {\,\begin{array}{*{20}{c}}{n\,!}&{\sin \,\left( {0 + \frac{{n\pi }}{2}} \right)}&{\cos \,\left( {0 + \frac{{n\pi }}{2}} \right)}\\{n\,!}&{\sin \,\left( {\frac{{n\pi }}{2}} \right)}&{\cos \,\left( {\frac{{n\pi }}{2}} \right)}\\a&{{a^2}}&{{a^3}}\end{array}\,} \right|\, = \,0$
{Since ${R_1} \equiv {R_2}$}.