How to draw pixel in picture box?

Using Bitmap, namely the Bitmap.SetPixel(). function Bitmap.SetPixel().

But if you want to draw graphics, then this is not the best way. There is a Chart element in Windows Forms. You can use it like this:

 chart->Series[0]->Points->AddXY(x, f(x)); 

There you can configure the type of interpolation function. I think the spline will be the most suitable for you.

This answer was in English so

 e.Graphics.FillRectangle(aBrush, x, y, 1, 1); 

In Windows Forms, the Chart tool is used for plotting. To select the type of "Chart", select in Properties -> Series -> Revenue property -> ChartType. In the drop-down list, select the desired type of chart. We consider the Chart methods using the following code as an example for constructing cosine and sine functions with comments:

 private void buttonCalc_Click(object sender, EventArgs e) { // Считываем с формы требуемые значения double Xmin = double.Parse(textBoxXmin.Text); double Xmax = double.Parse(textBoxXmax.Text); double Step = double.Parse(textBoxStep.Text); // Количество точек графика int count = (int)Math.Ceiling((Xmax - Xmin) / Step) + 1; // Массив значений X – общий для обоих графиков double[] x = new double[count]; // Два массива Y – по одному для каждого графика double[] y1 = new double[count]; double[] y2 = new double[count]; // Расчитываем точки для графиков функции for (int i = 0; i < count; i++) { // Вычисляем значение X x[i] = Xmin + Step * i; // Вычисляем значение функций в точке X y1[i] = Math.Sin(x[i]); y2[i] = Math.Cos(x[i]); } // Настраиваем оси графика chart1.ChartAreas[0].AxisX.Minimum = Xmin; chart1.ChartAreas[0].AxisX.Maximum = Xmax; // Определяем шаг сетки chart1.ChartAreas[0].AxisX.MajorGrid.Interval = Step; // Добавляем вычисленные значения в графики chart1.Series[0].Points.DataBindXY(x, y1); chart1.Series[1].Points.DataBindXY(x, y2); } 

Here is a link to an example .