---

using System;
using System.Windows.Forms;

namespace MyFirstApp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.Text = "3,4";
            textBox2.Text = "0,74";
            textBox3.Text = "19,43";
        }

        private void button1_Click(object sender, EventArgs e)
        {
            textBox4.Clear();

            double x = double.Parse(textBox1.Text);
            double y = double.Parse(textBox2.Text);
            double z = double.Parse(textBox3.Text);

            textBox4.Text = "X = " + x + Environment.NewLine;
            textBox4.Text += "Y = " + y + Environment.NewLine;
            textBox4.Text += "Z = " + z + Environment.NewLine;

            double a = Math.Tan(x + y) * Math.Tan(x + y);
            double b = Math.Exp(y - z);
            double c = Math.Sqrt(Math.Cos(x * x) + Math.Sin(z * z));
            double u = a - b * c;

            textBox4.Text += "Результат U = " + u;
        }
    }
}