derevo vyrazheniy

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Linq;
using System.Linq.Expressions;

namespace ConsoleApplication16
{
    class Program
    {
        static void Main(string[] args)
        {
            ParameterExpression result = Expression.Parameter(typeof(double), "result");
            ParameterExpression value = Expression.Parameter(typeof(double), "value");
            ParameterExpression i = Expression.Parameter(typeof(double), "i");
            ParameterExpression chisl = Expression.Parameter(typeof(double), "chisl");
            ParameterExpression znam = Expression.Parameter(typeof(double), "znam");

            LabelTarget label = Expression.Label(typeof(double));
            BlockExpression block = Expression.Block(
                new[] { result,  chisl, znam, i},
                Expression.Assign(result, Expression.Constant(0.0)),
                Expression.Assign(i, Expression.Constant(1.0)),
                Expression.Assign(chisl, value),
                Expression.MultiplyAssign(chisl, value),
                Expression.MultiplyAssign(chisl, value),
                Expression.Assign(znam, Expression.Constant(3.0)),
                Expression.Loop(
                    Expression.IfThenElse(
                        Expression.LessThan(i, Expression.Constant(1000.0)),
                        Expression.Block(
                            Expression.AddAssign(result, Expression.Divide(chisl, znam)),
                            Expression.Assign(znam, Expression.Constant(1.0)),
                            Expression.AddAssign(i, Expression.Constant(1.0)),
                            Expression.MultiplyAssign(chisl, value),
                            Expression.MultiplyAssign(chisl, value),
                            Expression.MultiplyAssign(znam, i),
                            Expression.MultiplyAssign(znam, i),
                            Expression.MultiplyAssign(znam, Expression.Constant(4.0)),
                            Expression.SubtractAssign(znam, Expression.Constant(1.0)),
                            Expression.MultiplyAssign(chisl, Expression.Constant(-1.0))
                            ),
                        Expression.Break(label, result)
                        ),
                    label
                    ), result

                );

            for (double x = 0.1; x < 1; x += 0.1)
            {
                double sum = Expression.Lambda<Func<double, double>>(block, value).Compile()(x);
                Console.WriteLine("{0}\t{1}", Math.Round(sum, 3), Math.Round((1 + x * x)*Math.Atan(x)/2 - x/2, 3));

            }



        }
    }
}