## Integration test post

At first, we sample in the ( is odd) equidistant points around :

[

f_k = f(x_k),: x_k = x^*+kh,: k=-frac{N-1}{2},dots,frac{N-1}{2}

]
where is some step.

Then we interpolate points by polynomial

begin{equation} label{eq:poly}

P_{N-1}(x)=sum_{j=0}^{N-1}{a_jx^j}

end{equation}

Its coefficients are found as a solution of system of linear equations:

begin{equation} label{eq:sys}

left{ P_{N-1}(x_k) = f_kright},quad k=-frac{N-1}{2},dots,frac{N-1}{2}

end{equation}

Here are references to existing equations: (ref{eq:poly}), (ref{eq:sys}).

Here is reference to non-existing equation (ref{eq:unknown}).