private void DrawBinaryTreeMCLauran(IFunction x) // draw McLaurin on the .PNG file
        {
            GraphVize.SaveDotFile(x, "abcd");
            Process dot = new Process();

            dot.StartInfo.FileName  = "dot.exe";
            dot.StartInfo.Arguments = "-T png -o abc.png abcd.dot";
            dot.Start();
            dot.WaitForExit();
        }
        private void DrawBinaryTree(IFunction x)
        {
            GraphVize.SaveDotFile(x, "abcd");
            Process dot = new Process();

            dot.StartInfo.FileName  = "dot.exe";
            dot.StartInfo.Arguments = "-T png -o abc.png abcd.dot";
            dot.Start();
            dot.WaitForExit();
            picBox_tree.ImageLocation = "abc.png";
        }