In inputbox input x and n
exponential function : e^x=1+ x/1! + x^2/2! +.....x^n/n! ; n!=1*2*3...*n
inside the function we can use t(n)=x^n/n! and for recurrence formula t(n)=t(n-1)*x/n
The partial sum to the n-th clause is expressed with s(n) which is ; s(n)=s(n-1)+t(n)
then e=1+s(n)
the calculation will repeat until i=n and |t(n)|<0.001
the problem is when i run the program the answer is no same with the exponential function above.
Sub e2()
Dim n As Double
Dim x As Double
Dim i As Double
Dim tn As Double
Dim sn As Double
Dim t1 As Double
Dim e As Double
x = CInt(InputBox("x?"))
n = CInt(InputBox("n?"))
Do
For i = 1 To n
t1 = x / (n - 1)
tn = (x / (n - 1)) * (x / n)
sn = tn + t1
e = 1 + sn
If x = 0 Then Exit For
Next i
Loop Until tn < 0.001 Or -tn < 0.001
MsgBox "e^" & CStr(x) & "=" & CStr(e)
End Sub
x = CInt(InputBox("x?"))
n = CInt(InputBox("n?"))
try
x = CDbl(InputBox("x?"))
n = CDbl(InputBox("n?"))