## Issue

I’m currently trying to implement a mathematic method to approximate

f(x) = 0. I’ve already implemented it in some languages and I want to do it in ruby now just for training.

But I have this error that I really does’nt understand

Here is my code

```
def fonction (x)
return (x ** 3) + 4 * (x ** 2) - 10
end
def derive (x)
return 3 * (x ** 2) + 8 * x
end
def newton(f, fPrime, n, u0)
if n == 0 then
return u0
else
uN = newton (f, fPrime, (n - 1), u0)
return uN - f(uN) / fPrime(uN)
end
end
for i in 0..6
puts (newton (fonction, derive, i, 2))
end
```

## Solution

i think there is space on newton method call

```
uN = newton (f, fPrime, (n - 1), u0) # there is space after newton
```

also in this one

```
for i in 0..6
puts (newton (fonction, derive, i, 2)) # there is space after newton
end
```

try remove it, and you will see another error i guess, i try it on repl

Answered By – dedypuji

Answer Checked By – Terry (BugsFixing Volunteer)