public DaThuc Lagrange()
{
var length = bangSo.N;
var D1y = new MaTran(1, length);
for (int i = 0; i < length; i++)
{
D1y[0, i] = 1;
}
for (int i = 0; i < length; i++)
{
for (int j = 0; j < length; j++)
{
if (i == j)
{
continue;
}
D1y[0, i] *= bangSo[0, i] - bangSo[0, j];
}
D1y[0, i] = bangSo[1, i] / D1y[0, i];
}
var ketQua = new DaThuc();
for (int i = 0; i < length; i++)
{
var temp = new DaThuc();
temp[0] = 1;
for (int j = 0; j < length; j++)
{
if (i == j)
{
continue;
}
var temp2 = new DaThuc();
temp2[1] = 1;
temp2[0] = -bangSo[0, j];
temp = temp.NhanVoiDaThucBac1(temp2);
}
temp = temp * D1y[0, i];
ketQua = ketQua + temp;
}
return ketQua;
}
public DaThuc NewtonTongQuat()
{
var length = bangSo.N;
var bangTiHieu = new MaTran(length, length);
for (int i = 0; i < length; i++)
{
bangTiHieu[i, 0] = bangSo[1, i];
}
for (int i = 1; i < length; i++)
{
for (int j = 0; j < length - i; j++)
{
var tuSo = bangTiHieu[j + 1, i - 1] - bangTiHieu[j, i - 1];
var mauSo = bangSo[0, j + i] - bangSo[0, j];
bangTiHieu[j, i] = tuSo / mauSo;
}
}
var ketQua = new DaThuc();
ketQua[0] = bangTiHieu[0, 0];
for (int i = 0; i < length - 1; i++)
{
var temp = new DaThuc();
temp[0] = 1;
for (int j = 0; j < i+1; j++)
{
var temp2 = new DaThuc();
temp2[1] = 1;
temp2[0] = -bangSo[0, j];
temp = temp.NhanVoiDaThucBac1(temp2);
}
temp = temp * bangTiHieu[0,i+1];
ketQua = ketQua + temp;
}
return ketQua;
}
