避免落入局部最优解，只要让步长够长即可。
x1 = resultX1 + random1.NextDouble()*100; 如果后面不乘以100，则很大概率落入负数的最大值

            Random random1 = new Random(DateTime.Now.Millisecond);double x1 = 0, resultX1=0,max=-999999,maxTemp=0;for (int i = 0; i < 54321; i++){if (random1.Next(0, 100) % 2 == 0){x1 = resultX1 + random1.NextDouble()*100;//加大后面的100，即可}else{x1 = resultX1 - random1.NextDouble()*100;}maxTemp = Math.Pow(x1, 4) * (-1) + Math.Pow(x1, 3) + 6 * Math.Pow(x1, 2) + 5;if (maxTemp > max){resultX1 = x1;max = maxTemp;}}textBox1.Text = resultX1.ToString();textBox2.Text = max.ToString();