If O be the origin and the coordinates of P be (1, 2, -3),then find the equation of the plane passing through P and perpendicular to OP.
The coordinates of the points, O and P, are (0, 0, 0) and (1, 2, -3) respectively.
Therefore, the direction ratios of OP are (1-0) =1, (2-0)=2, and (-3-0)=-3
It is known that the equation of the plane passing through the point(x1, y1, z1) is a(x-x1) + b(y-y1) + c(z-z1) = 0
where, a, b, and c are the direction ratios of normal.
Here, the direction ratios of normal are 1, 2, and -3, and the point P is (1, 2, -3).
Thus, the equation of the required plane is 1(x-1) + 2(y-2) - 3(z+3) = 0
⇒ x+2y-3z-14 = 0
Let the lines $L_1 : \vec r = \hat i + 2\hat j + 3\hat k + \lambda(2\hat i + 3\hat j + 4\hat k)$, $\lambda \in \mathbb{R}$ and $L_2 : \vec r = (4\hat i + \hat j) + \mu(5\hat i + + 2\hat j + \hat k)$, $\mu \in \mathbb{R}$ intersect at the point $R$. Let $P$ and $Q$ be the points lying on lines $L_1$ and $L_2$, respectively, such that $|PR|=\sqrt{29}$ and $|PQ|=\sqrt{\frac{47}{3}}$. If the point $P$ lies in the first octant, then $27(QR)^2$ is equal to}