Let the vertices of a triangle are A\((x_1, y_1, z_1)\), B\((x_2, y_2, z_2)\) and C\((x_3, y_3, z_3)\). The mid-points of sides AB, BC and CA are F(2, 3, −1), D(5, 7, 11) and E(0, 8, 5) respectively. Find \(x_1 + x_2\).
Consider a tetrahedron D—ABC with position vectors of its angular points as A(1, 1, 1); B(1, 2, 3); C(1, 1, 2) and centre of tetrahedron \left(\frac{3}{2}, \frac{3}{4}, 2\right). Find the shortest distance between the skew lines AB and CD.
Let the point, on the line passing through the points $P(1,-2,3)$ and $Q(5,-4,7)$, farther from the origin and at distance of 9 units from the point $P$, be $(\alpha,\beta,\gamma)$. Then $\alpha^2+\beta^2+\gamma^2$ is equal to:
Let $\alpha x + \beta y + yz = 1$ be the equation of a plane passing through the point $(3, -2, 5)$ and perpendicular to the line joining the points $(1, 2, 3)$ and $(-2, 3, 5)$. Then the value of $\alpha\beta y$ is equal to _____.
If the length of the perpendicular from point $P(a, 4, 2)$, $a>0$, to the line $\dfrac{x+1}{2}=\dfrac{y-3}{3}=\dfrac{z-1}{-1}$ is $2\sqrt{6}$ units, and $Q(\alpha_1,\alpha_2,\alpha_3)$ is the image of $P$ on this line, then $a+\displaystyle\sum_{i=1}^3 \alpha_i$ equals