var j = 0; j < synthesis_n-1; ++j)
        A[synthesis_n-1][j+1] = Math.pow(synthesis_xs[synthesis_n-2], j) * (j+1);
    A[synthesis_n-1][0] = 0.0;
    B[synthesis_n-1] = (synthesis_ys[synthesis_n-1] - synthesis_ys[synthesis_n-2]) / (synthesis_xs[synthesis_n-1] - synthesis_xs[synthesis_n-2]);

    synthesis_system = document.getElementById("synthesis_system");
    synthesis_system.innerHTML = "P(x<sub>1</sub>)' = "+A[0][3].toFixed(1)+"a + "+A[0][2].toFixed(1)+"b + "+A[0][1].toFixed(1)+"c = "+B[0].toFixed(1)