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diff --git a/845/CH6/EX6.23/Ex6_23.sce b/845/CH6/EX6.23/Ex6_23.sce
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+//Example 6.23
+
+clc
+clear
+
+x = [-1 1 2 3];
+y = [-21 15 12 3];
+
+n = length(x);
+X = poly(0, "X");
+Y = 0;
+for i = 1:n
+    t = x;
+    t(i) = [];
+    p = 1;
+    for j = 1:length(t)
+        p = p * (X-t(j))/(x(i)-t(j));
+    end
+    Y = Y + p*y(i);
+end
+
+dydx = derivat(Y);
+extx = real(roots(dydx));
+extx = round(extx*10^4)/10^4;
+d2ydx = derivat(dydx);
+
+if  horner(d2ydx,extx(1)) < 0 then
+    maxx = extx(1);
+    maxy = horner(Y,maxx);
+else
+    maxx = extx(2);
+    maxy = horner(Y,maxx);
+end
+maxy = round(maxy*10^4)/10^4;
+disp(maxx,"max_x = ")
+disp(maxy,"max_y = ")