Hi there,

As a student I am new to python and am struggling with the following program I have been tasked to create. My code so far is like so. The idea is that the function will take a guess x, incorporate an arbitrary function f(x) and then take feps, a tolerance and max_it, the maximum number of iterations. The general idea is that this iterative approach will use the Newton_Raphson method to determin an approximation to the given value x. Example, def f(x): return x**2-2 and then newton(f,1.0,0.2,15) yields approx squared root of two - 1.414.......

```
def newton(f,x,feps,max_it):
it=0
def fprime(x):
return (f(x+feps/2.0)-f(x-feps/2.0))/feps
while abs(f(x))>feps:
x=x-f(x)/fprime(x)
it+=1
if it>max_it:
return None
return x
```

This seems to work well but I cannot get it to return the python special type - None if the number of iterations are exceeded during the while loop.

Any suggestions would be fantastic as I have now spent an embarrasing number of hours on it.

*Edited 6 Years Ago by vegaseat*: added code tags