Table 2.

Modeling of the reflection functions: Group N—dental pressed ceramics.

x	$\left[0,x_i\right)=\left[0,2\right)$	$\left[x_i,x_{\max }\right)=\left[2,3.25\right)$
ρ(x)	$f(x)=\frac{{\rho }_{\max }-{\rho }_0}{x_M}\left(-\frac{x^2}{x_M}+2x\right)+{\rho }_0$	$\begin{array}{l}g(x)=\frac{{\rho }_i-{\rho }_0}{{\left(x_{\max }-x_i\right)}^2}x\left(x-2x_{\max }\right)+\\ +\frac{{\rho }_i{x}_{\max }^2-{\rho }_0\left(2x_{\max }-x_i\right)x_i}{{\left(x_{\max }-x_i\right)}^2}\end{array}$
	$f(x)=-9.6x^2+24x+60$	$g(x)=6.4x^2-41.6x+127.6$
dρ/dx	$f^{\prime }(x)=2\frac{{\rho }_{\max }-{\rho }_0}{x_m}\left(-\frac{x}{x_M}+1\right)$	$g^{\prime }(x)=2\frac{{\rho }_i-{\rho }_0}{{\left(x_{\max }-x_i\right)}^2}\left(x-x_{\max }\right)$
	$f^{\prime }(x)=-19.2\cdot x+24$	$g^{\prime }(x)=12.8\cdot x-41.6$
d2ρ/dx2	$f^{″}(x)=-2\frac{\left({\rho }_{\max }-{\rho }_0\right)}{x_m^2}=-19.2{\mathrm{mm}}^{-2}$	$g^{″}(x)=2\frac{{\rho }_i-{\rho }_0}{{\left(x_{\max }-x_i\right)}^2}=12.8{\mathrm{mm}}^{-2}$