Math.lab5

#include <stdio.h>

const float X[] = {2.0,2.3,2.5,3.0,3.5,3.8,4.0};
const float Y[] = {5.848,6.127,6.300,6.694,7.047,7.243,7.368};
const float x = 3.34;

float solve();

int main()
{
    printf("\nf(%.2f) = %f\n\n", x, solve());

    return 0;
}

float solve()
{
    int i, k, n = 7;
    float S = 0, W = 1, w;

    for (k = 0; k < n; k++)
        W *= x - X[k];

    for (k = 0; k < n; k++) {
        w = 1;
        for (i = 0; i < n; i++) {
            if (i != k)
                w *= X[k] - X[i];

        }
        S += (W * Y[k]) / ((x - X[k]) * w);
    }

    return S;
}