what is this?! PLEASE HELP

My balls/divided_diff.m

@@ -0,0 +1,20 @@
+x = 1.8;
+X = [1.7 1.9 2 2.1 2.3];
+f = @(x) e.^x;
+function solution = divided_diff(x, X, f)
+	Sigma = 0;
+	for j = [1:length(X)]
+		w = 1;
+
+		for k = [1:length(X)]
+			if(j != k)
+			w = w * ( X(j) - X(k) );
+			endif
+		endfor
+
+		Sigma = Sigma + ( f(j) / w );
+	endfor
+	solution = Sigma;
+endfunction
+balls = divided_diff(x,X,f)
+