Проверьте программу. Не правильно вычисляется интеграл

Option Explicit
 
Function w(z As Integer)
Dim sum As Double, p As Double, m As Double, n As Long
Dim i As Integer, j As Integer
Dim eps!, q
Dim s
s = 0 ''
i = 1: p = z: m = z: eps! = 0.01
'q = CInt(InputBox("Введи q", "Ввод"))
q = 2
Do While m > eps
s = s + m:
i = i + 1
p = p * z * Log(q)
      n = 1
For j = 1 To i - 1
   n = n * j
Next j
m = p / n
Loop
w = s
End Function
 
Function fab(p As Integer, q As Integer) As Double
fab = 2.7182 ^ (p - q)
End Function
 
Function f(x As Double)
f = 1 / ((1 + x + x ^ 2) ^ (1 / 2))
End Function
 
Function integ(x As Double, y As Double, n As Integer) As Double
Dim i As Double
For i = x To y Step (y - x) / (n - 1)
If (i = x) Or (i = y) Then
integ = integ + 0.5 * f(i)
Else: integ = integ + f(i)
End If
Next
integ = integ * (y - x) / (n - 1)
End Function
 
Sub main()
Const e = 2.7182
Dim a#, b#, c#, d#, n%, x1%, x2%, y1%, y2%, o%
Dim functional#
'x1 = CInt(InputBox("Введи x1", "Ввод", 2))
x1 = 1
'x2 = CInt(InputBox("Введи x2", "Ввод ", 2))
x2 = 2
'y1 = CInt(InputBox("Введи y1", "Ввод ", 1))
y1 = 1
'y2 = CInt(InputBox("Введи y2", "Ввод ", 1))
y2 = 2
'n = CInt(InputBox(" Введи n", " Ввод ", 51))
n = 10
a = ((e ^ (x1)) ^ 2) / (2 * fab(x1, y1) + (fab(x2, y2)) ^ (1 / 2))
b = 18 / (fab(y1, y2) + fab(x1, x2) ^ (1 / 2))
c = 20 / (w(2) ^ (1 / 2))
d = 36 / (w(2) ^ (1 / 2))
Dim int1, int2, int3, int4, t, u, p, func, j
int1 = integ(a, b, n)
int2 = integ(a, d, n)
int3 = integ(b, c, n)
int4 = integ(b, d, n)
t = integ(a, b, n): u = integ(a, d, n): o = integ(b, c, n): p = integ(b, d, n)
func = (int1 - int2) / (int3 + int4)
Cells(1, 1) = c
Cells(1, 2) = 1 / (Cells(1, 1) ^ 2 + 1)
For j = 2 To n
Cells(j, 1) = Cells(j - 1, 1) + (b - c) / (n - 1)
Cells(j, 2) = 1 / (Cells(j, 1) ^ 2 + 1)
Next
MsgBox "a=" & a: MsgBox "b=" & b: MsgBox "c=" & c: MsgBox "d=" & d
MsgBox "int1=" & int1: MsgBox "int2=" & int2: MsgBox "int3=" & int3: MsgBox "int4=" & int4
MsgBox "F=" & func
End Sub