3D Geometry Questions (578)

Let $(\alpha,\beta,\gamma)$ be the image of the point $(8,5,7)$ in the line $\dfrac{x-1}{2}=\dfrac{y+1}{3}=\dfrac{z-2}{5}$. Then $\alpha+\beta+\gamma$ is equal to:
The shortest distance between the lines $\dfrac{x-3}{2}=\dfrac{y+15}{-7}=\dfrac{z-9}{5}$ and $\dfrac{x+1}{2}=\dfrac{y-1}{1}=\dfrac{z-9}{-3}$ is:
The square of the distance of the image of the point $(6,1,5)$ in the line $\dfrac{x-1}{3}=\dfrac{y}{2}=\dfrac{z-2}{4}$, from the origin is _____
If the shortest distance between the lines $L_1:\vec{r}=(2+\lambda)\hat{i}+(1-3\lambda)\hat{j}+(3+4\lambda)\hat{k}$, $\lambda\in\mathbb{R}$ and $L_2:\vec{r}=2(1+\mu)\hat{i}+3(1+\mu)\hat{j}+(5+\mu)\hat{k}$, $\mu\in\mathbb{R}$ is $\dfrac{m}{\sqrt{n}}$, where $\gcd(m,n)=1$, then the value of $m+n$ equals:
Let $P(\alpha,\beta,\gamma)$ be the image of the point $Q(3,-3,1)$ in the line $\dfrac{x-0}{1}=\dfrac{y-3}{1}=\dfrac{z-1}{-1}$ and $R$ be the point $(2,5,-1)$. If the area of triangle $PQR$ is $\lambda$ and $\lambda^2=14K$, then $K$ is equal to:
Let the position vectors of the vertices $A$, $B$ and $C$ of a triangle be $2\hat{i}+2\hat{j}+\hat{k}$, $\hat{i}+2\hat{j}+2\hat{k}$ and $2\hat{i}+\hat{j}+2\hat{k}$ respectively. Let $l_1,l_2$ and $l_3$ be the lengths of perpendiculars drawn from the orthocentre of the triangle on the sides $AB$, $BC$ and $CA$ respectively, then $l_1^2+l_2^2+l_3^2$ equals:
A point P moves in the space such that \(3PA = 2PB\), then the locus of P is
Given lines can be written in vector forms as \(\vec{r} = (2\hat{i} + 3\hat{j} + 4\hat{k}) + \lambda(\hat{i} + \hat{j} - k\hat{k})\) and \(\vec{l} = (\hat{i} + 4\hat{j} + 5\hat{k}) + u(k\hat{i} + 2\hat{j} + \hat{k})\). The two lines will be coplanar if:
Let \(P(3, 2, 6)\) be a point in space and \(Q\) be a point on the line \(\vec{r} = (\hat{i} - \hat{j} + 2\hat{k}) + \mu(-3\hat{i} + \hat{j} + 5\hat{k})\). Then the value of \(\mu\) for which the vector \(\overrightarrow{PQ}\) is parallel to the plane \(x - 4y + 3z = 1\) is
Given \(\vec{r} \cdot (\hat{i} + 2\hat{j} + 2\hat{k}) = 15\) (a plane) and \(|\vec{r} - (\hat{j} + 2\hat{k})| = 4\) (a sphere with centre \((0,1,2)\) and radius 4). The centre of the circle formed by their intersection is:
Given a tetrahedron has vertices P(1, 2, 1), Q(2, 1, 3), R(−1, 1, 2) and O(0, 0, 0). The angle between the faces OPQ and PQR is:
The plane passing through the point (4, –1, 2) and parallel to the lines \(\dfrac{x+2}{3} = \dfrac{y-2}{-1} = \dfrac{z+1}{2}\) and \(\dfrac{x-2}{1} = \dfrac{y-3}{2} = \dfrac{z-4}{3}\) also passes through the point:
If $\vec{a}=\hat{i}+2\hat{j}+3\hat{k}$, $\vec{b}=2\hat{i}+7\hat{j}+2\hat{k}$, $\vec{x}\cdot\vec{a}=0$ and $\vec{x}\cdot\vec{c}=0$ for some non-zero vector $\vec{x}$, then value of $\vec{a}\cdot(\vec{b}\times\vec{c})$ is
The image of the line \(\dfrac{x-1}{3} = \dfrac{y-3}{1} = \dfrac{z-4}{-5}\) in the plane \(2x - y + z + 3 = 0\) is the line
The minimum value of $x^2+y^2+z^2$ if $ax+by+cz=p$ is
Line $\frac{x}{1}=\frac{6-y}{2}=\frac{z+8}{5}$ meets $\frac{x-5}{4}=\frac{y-7}{3}=\frac{z+2}{1}$ at $A$ and $\frac{x+3}{6}=\frac{3-y}{3}=\frac{z-6}{1}$ at $B$. Distance of midpoint of $AB$ from $2x-2y+z=14$ is
Let the direction ratios (DRs) of a line be \(\cos\left(\dfrac{\pi}{4}\right),\; \cos\left(\dfrac{\pi}{4}\right),\; \cos\theta\). The angle the line makes with the positive direction of z-axis is:
Given the planes x + 2y − 3z + 5 = 0 and 2x + y + 3z + 1 = 0. If a point P is (2, −1, 2), then
A line in the 3-dimensional space makes an angle \(\theta\,(0
Given lines \(\dfrac{x}{2} = \dfrac{y}{2} = \dfrac{z}{1}\) and \(\dfrac{x-5}{2} = \dfrac{y-2}{p/7} = \dfrac{z-3}{4}\). The value of \(p\) such that the angle between both lines satisfies \(\cos^{-1}\left(\dfrac{2}{3}\right)\) is:
Let \(P \equiv (3, 4, a)\) and \(Q \equiv (3, 4, \lambda + a)\) be two points. The area of triangle \(OPQ\) (where \(O\) is the origin) is \(\frac{5}{4}[(a+1)^2 + 5]\). If the least area is \(\frac{p}{q}\) (in lowest terms), find \(p + q\).
The plane containing the line \(\dfrac{x-3}{2} = \dfrac{y+2}{-1} = \dfrac{z-1}{3}\) and also containing its projection on the plane \(2x + 3y - z = 5\), contains which one of the following points?
The equation of the reflected ray is the line joining Q(6, 5, -2) and B(-10, -15, -14). Express this in standard form.
For what value of $a$ do three planes $x + y + z = 1$, $x + 2ay + z = 1$, and $ax^2 + y + z = 1$ intersect in a line?
182. In a tetrahedron \(OABC\), if \(\vec{OA} = \vec{i}\), \(\vec{OB} = \vec{i} + \vec{j}\) and \(\vec{OC} = \vec{i} + 2\vec{j} + \vec{k}\), if shortest distance between edges \(OA\) and \(BC\) is \(m\), then \(2m\) is equal to \(\ldots\) (Where \(O\) is the origin)
Ex. 46 Two lines whose equations are \(\frac{x}{-2} = \frac{y}{-3} = \frac{z}{-2}\) and \(\frac{x-3}{2} = \frac{y-2}{3} = \frac{z-1}{\lambda}\) lie in the same plane.The value of \(\sin^{-1} \sin \lambda\) is equal to
A line with direction cosines proportional to 2, 1, 2 meets each of the lines \(x = y + a = z\) and \(x + a = 2y = 2z\). The co-ordinates of each point of intersection are given by
Two spheres \(x^2 + y^2 + z^2 + 7x - 2y - z - 13 = 0\) and \(x^2 + y^2 + z^2 - 3x + 3y + 4z - 8 = 0\) intersect. The plane of intersection is:
In a three dimensional coordinate system P, Q and R are images of a point A(a, b, c) in the XY, YZ and the ZX planes respectively. If G is the centroid of triangle PQR, then area of triangle AOG is (O is the origin)
If the plane \(2ax - 3ay + 4az + 6 = 0\) passes through the midpoint of the line joining the centres of the spheres \(x^2 + y^2 + z^2 + 6x - 8y - 2z = 13\) and \(x^2 + y^2 + z^2 - 10x + 4y - 2z = 8\), then a equals
The line of intersection of the planes, \(\vec{r} \cdot (3\hat{i} - \hat{j} + \hat{k}) = 1\) and \(\vec{r} \cdot (\hat{i} + 4\hat{j} - 2\hat{k}) = 2\), is
Lines are \(\dfrac{x}{0} = \dfrac{y}{0} = \dfrac{z}{1} = \lambda\) (z axis) and \(x + y + 2z - 3 = 0,\ 2x + 3y + 4z - 4 = 0\). The shortest distance (S.D.) between the two lines is given by \(\text{S.D.} = \dfrac{|(\vec{c}-\vec{a})\cdot(\vec{b}\times\vec{d})|}{|\vec{b}\times\vec{d}|}\). Find the shortest distance.
A variable plane at a distance of 1 unit from the origin cuts the coordinate axes at A, B and C. If the centroid D(x, y, z) of triangle ABC satisfies the relation \(\dfrac{1}{x^2} + \dfrac{1}{y^2} + \dfrac{1}{z^2} = k\), then the value of k is __________.
The sum of the intercepts on the coordinate axes of the plane passing through the point (–2, –2, 2) and containing the line joining the points (1, –1, 2) and (1, 1, 1), is
The shortest distance between the lines \(\dfrac{x}{2} = \dfrac{y}{2} = \dfrac{z}{1}\) and \(\dfrac{x+2}{-1} = \dfrac{y-4}{8} = \dfrac{z-5}{4}\) lies in the interval
The coordinates of a point on the plane 2x + y - 5z = 0, which is $$2\sqrt{11}$$ units away from the line of intersection of 2x + y - 5z = 0 and 4x - 3y + 7z = 0 are:
If the equation of the plane passing through the point \((-1, 2, 0)\) and parallel to the lines \(\dfrac{x}{3} = \dfrac{y+1}{0} = \dfrac{z-2}{-1}\) and \(\dfrac{x-1}{1} = \dfrac{y+1}{2} = \dfrac{z+1}{-1}\) is \(ax + by + cz = 1\), then the value of \((a + b + c)\) is:
The equation of the plane containing the line \(2x - 5y + z = 3\); \(x + y + 4z = 5\), and parallel to the plane, \(x + 3y + 6z = 1\), is
A line \(AB\) in three-dimensional space makes angles \(45°\) and \(120°\) with the positive \(x\)-axis and the positive \(y\)-axis, respectively. If \(AB\) makes an acute angle \(\theta\) with the positive \(z\)-axis, then \(\theta\) equals
If the image of the point \(P(1, -2, 3)\) in the plane, \(2x + 3y - 4z + 22 = 0\) measured parallel to the line, \(\dfrac{x}{1} = \dfrac{y}{4} = \dfrac{z}{5}\) is \(Q\), then \(PQ\) is equal to
The point of intersection of the plane \(\vec{r} \cdot (3\hat{i} - 5\hat{j} + 2\hat{k}) = 6\) with the straight line passing through the origin and perpendicular to the plane \(2x - y - z = 4\), is \((x_0, y_0, z_0)\). The value of \((2x_0 - 3y_0 + z_0)\), is:
Let P(x, y, z) be any point on the locus, then the distances from the six faces are |x + 1|, |x − 1|, |y + 1|, |y − 1|, |z + 1| and |z − 1|. According to the given condition, find the locus of P.\(|x+1|^2 + |x-1|^2 + |y+1|^2 + |y-1|^2 + |z+1|^2 + |z-1|^2 = 10\)
83. We have three planes\(P_1: 2x - y + 2z + 3 = 0\)\(P_2: 2x - y + 2z + \lambda/2 = 0\)\(P_3: 2x - y + 2z + \mu = 0\)Given that the distance between \(P_1\) and \(P_2\) is \(\frac{1}{3}\) and the distance between \(P_1\) and \(P_3\) is \(\frac{2}{3}\). Find \(\lambda_{\max} + \mu_{\max}\).
Given lines are: \(\vec{r} = (\hat{i} + (-3\hat{j}) + \hat{k}) + s(\hat{i} - \lambda\hat{j} + \lambda\hat{k})\) and \(\vec{r} = (0\hat{i} + \hat{j} + 2\hat{k}) + t\left(\dfrac{1}{2}\hat{i} + \hat{j} - \hat{k}\right)\). If \(\vec{a} = (1-0)\hat{i} + (-3-1)\hat{j} + (1-2)\hat{k}\), \(\vec{b} = \hat{i} - \lambda\hat{j} + \lambda\hat{k}\), and \(\vec{c} = \dfrac{1}{2}\hat{i} + \hat{j} - \hat{k}\) are coplanar, then \(\lambda\) equals:
Given planes \(3x + 4y + z = 1\) and \(5x + 8y + 2z + 14 = 0\). The sine of the angle between the plane \(x + y + z = 5\) and the line of intersection of the two given planes is:
The lines \(\dfrac{x-2}{1} = \dfrac{y-3}{1} = \dfrac{z-4}{-k}\) and \(\dfrac{x-1}{k} = \dfrac{y-4}{2} = \dfrac{z-5}{1}\) are coplanar is
Equation of the line through the point (1, 1, 1) and intersecting the lines \(2x - y - z - 2 = 0 = x + y + z - 1\) and \(x - y - z - 3 = 0 = 2x + 4y - z - 4\)
The point of intersection of the plane \(\vec{r} \cdot (3\hat{i} - 5\hat{j} + 2\hat{k}) = 6\) with the straight line passing through the origin and perpendicular to the plane \(2x - y - z = 4\), is \((x_0, y_0, z_0)\). The value of \((2x_0 - 3y_0 + z_0)\) is:
A plane containing the point \((3, 2, 0)\) and the line \(\dfrac{x-1}{1} = \dfrac{y-2}{5} = \dfrac{z-3}{4}\) also contains the point
A plane passes through the point \((1, 1, 1)\). If \(b, c, a\) are the direction ratios of a normal to the plane where \(a, b, c\) (\(a