Dear all,

I am implementing the divided differences of Newton’ polynomial. However a strange thing happens.

I define the x and y values by X and Y variables. Inside the function I define the vector \Delta Y = Y.

But, at the end of the execution, I miss the Y value (because \Delta Y changes).

How can I fix this?

Below, my code:

```
function Diferencas_Divididas(X,Y)
n=length(X)
Δy = Y
a = zeros(n)
a[1] = Y[1]
for i in 1:n-1
for j in 1:n-i
Δy[j] = (Δy[j+1] - Δy[j]) / (X[j+i] - X[j])
end
a[i+1] = Δy[1]
end
return a
end
X = [2 2.5 3 3.5]
Y = [7.4 12.2 20.1 33.4]
n=length(X)
a = Diferencas_Divididas(X,Y)
julia> Y
1×4 Array{Float64,2}:
3.06667 10.8 26.6 33.4
julia>
´´´
```