Re: derivatives and determinant

It was a typo in my first message
Let f(x)=(x-x_1)(x-x_2)...(x-x_n)where the numbers x_1,x_2,...,x_n-pairwise distinct and a_{ii}=f''(x_i), a_{ij}=(f'(x_i)-f'(x_j))/(x_i-x_j). i \neq j.
1<=i,j<=n.

Now, A mustn't be always diagonal.
.