代码“TypeError：只能将列表（而不是“int”）连接到列表中的错误？

实现牛顿法。有我不明白的错误。

deriveF_y对一个返回非整数数字的函数发誓，并且为了将该数字附加到列表中存在问题。

出了什么问题，如何纠正？

编码：

import math

def funcF(x, y):
    return((2 * x) - math.cos(y + 1)) # math.sin(x + 1) - y - 1.2

def funcG(x, y):
    return(y + math.sin(x) + 0.4) # 2 * x + math.cos(y) - 2

def derivedF_x(x):
    return(2) # math.cos(x + 1)

def derivedG_x(x):
    return (math.cos(x)) # 2

def derivedF_y(y):
    return (math.sin(y + 1)) # -1

def derivedG_y(y):
    return(1) # -math.sin(y)

def Determ(func1, func2, func3, func4):
    return(func1 * func4 - func2 * func3)

def NewtonMethod(el_x, el_y):
    e = 0.0001
    k = 0
    dN = Hn = Kn = 0
    dN = Determ(derivedF_x(el_x), derivedF_y(y), derivedG_x(x), derivedG_y(el_y))
    Hn = Determ(derivedF_y(y), funcF(el_x, el_y), derivedG_y(el_y), funcG(el_x, el_y)) / dN
    Kn = Determ(funcF(el_x, el_y), derivedF_x(el_x), funcG(el_x, el_y), derivedG_x()) / dN
    
    #Нахождение корней сис-мы
    while(abs(Hn) >= e and abs(Kn) >= e):
        el_x += Hn
        el_y += Kn
        dN = Determ(derivedF_x(el_x), derivedF_y(y), derivedG_x(x), derivedG_y(el_y))
        Hn = Determ(derivedF_y(y), funcF(el_x, el_y), derivedG_y(el_y), funcG(el_x, el_y)) / dN
        Kn = Determ(funcF(el_x, el_y), derivedF_x(el_x), funcG(el_x, el_y), derivedG_x()) / dN
        k += 1
    print("\nКорни системы:")
    print(" x =", "%.5f" % el_x, "y = ", "%.5f" % el_y)
    print("Количество итераций:", k)

arg = [-3, -2.6, -2.2, -1.8, -1.4, -1, -0.6, -0.2, 0.2, 0.6, 1]
x, y = [], []

#Заполнение значениями ф-й
for i in arg:
    y.append(math.cos(i + 1) / 2) # math.sin(i + 1) - 1.2
    x.append(-math.sin(i)-0.4) # -math.cos(i)/2 + 1

#Определение начальных точек
el_x, el_y = x[5], y[5]
print("Начальные точки приближения:\n x =", "%.2f" % el_x, "\n y =", el_y)

NewtonMethod(el_x, el_y)

错误文字：

Traceback (most recent call last):
  File "./prog.py", line 56, in <module>
  File "./prog.py", line 28, in NewtonMethod
  File "./prog.py", line 16, in derivedF_y
TypeError: can only concatenate list (not "int") to list