pointToRay3d

    double x, y, z, e1, e2, e3, v1, v2, v3, d, xVectorFromEToP, dirVectorMagnitude,  vectorEPMagnitude, yVectorFromEToP, zVectorFromEToP, dotProductEpV, cpX, cpY, cpZ;
    cin >> x >> y >> z >> e1 >> e2 >> e3 >> v1 >> v2 >> v3;

    xVectorFromEToP = x - e1;
    yVectorFromEToP = y - e2;
    zVectorFromEToP = z - e3;
    dotProductEpV = ((xVectorFromEToP * v1) + (yVectorFromEToP * v2) + (zVectorFromEToP * v3));

    if (dotProductEpV >= 0) {
        cpX = ((v2 * zVectorFromEToP) - (v3 * yVectorFromEToP));
        cpY = ((v1 * zVectorFromEToP) - (v3 * xVectorFromEToP)) * -1;
        cpZ = ((v1 * yVectorFromEToP) - (v2 * xVectorFromEToP));

        vectorEPMagnitude = sqrt(pow(cpX, 2) + pow(cpY, 2) + pow(cpZ, 2));
        dirVectorMagnitude = sqrt(pow(v1, 2) + pow(v2, 2) + pow(v3, 2));

        d = vectorEPMagnitude / dirVectorMagnitude;
        if (d < 1e-8)
            cout << 1;
    } else {
        cout << 0;
    }