# Interpolation- Lagrange polynomial

Let $$x_0,x_1,...,x_n$$ will be different real numbers. Show, that: $$f[x_0,x_1,...,x_n]=\sum_{i=0}^m\frac{f(x_i)}{\Phi '(x)}$$ where $$\Phi (x)=(x-x_0)(x-x_1)...(x-x_m)$$ So, I have some problems.How to start?

I guess $$f$$ is defined as the minimum polynomial with $$f(x_i)=y_i$$. You get two polynomials of same order $$n$$, equal on $$n+1$$ points. They are equal.