function question_43
clear;clc;close all;tic;
[a,b,c] = meshgrid(-pi:pi,-pi:pi,-pi:pi);
D=2*(1-cos(b).*cos(b).*cos(a+c)-sin(b).*sin(b).*cos(a-c));
xslice = [-1.2,.8,2];
yslice = 2;
zslice = [-2,0];
slice(a,b,c,D,xslice,yslice,zslice)
colormap hsv
colorbar;
toc
end