3D Geometry Questions (578)

The angle between the lines whose direction cosines satisfy the equations \(l + m + n = 0\) and \(l^2 = m^2 + n^2\) is
The line $(x,y,z)=(2,-3,4)+\lambda(1,2,-3)$ intersects $2x+3y-z=13$ at $P$ and $yz$-plane at $Q$. If $PQ=a\sqrt{b}$, $a,b\in\mathbb{N}$, $a>3$, then $\dfrac{a+b}{3}$ equals
If direction cosines of line \(L\) be \(l, m, n\), and \(2l + 3m + n = 0\) and \(l + 3m + 2n = 0\), then what is \(\cos\alpha\) where \(\alpha\) is the angle the line makes with the x-axis?
For lines \(\frac{x-1}{1} = \frac{y-2}{2} = \frac{z+3}{\lambda^2}\) and \(\frac{x-3}{1} = \frac{y-2}{\lambda^2} = \frac{z-1}{2}\) to be coplanar, the number of values of \(\lambda\) is:
The vector equation of the line passing through the point \((1, 2, -4)\) and perpendicular to the two lines \(\frac{x - 8}{3} = \frac{y + 19}{-16} = \frac{z - 10}{7}\) and \(\frac{x - 15}{3} = \frac{y - 29}{8} = \frac{z - 5}{-5}\) is
Let $\vec{a}$, $\vec{b}$, $\vec{c}$ have magnitudes 1, 2, 3 respectively, satisfying $|(\vec{a}\times\vec{b})\cdot\vec{c}|=6$. If $\vec{d}$ is a unit vector coplanar with $\vec{b}$ and $\vec{c}$ such that $\vec{b}\cdot\vec{d}=1$, then $|(\vec{a}\times\vec{c})\cdot\vec{d}|^2+|(\vec{a}\times\vec{c})\times\vec{d}|^2$ is
In a cubical hall ABCD-PQRS with each side 10 m, G is the centre of the wall BCRQ and T is the mid-point of the side AB. The angle of elevation of G at the point T is
The centre of the sphere (x-4)(x+4) + (y-3)(y+3) + z^2 = 0 is
The equation of the plane $P_1$ parallel to line $L: \frac{x-1}{2}=\frac{y-0}{3}=\frac{z-1}{1}$, at distance 6 from the intersection of $L$ with plane $P: 2x+3y+z-18=0$, and having maximum distance from $Q(5,4,-4)$, is $ax+by+cz+d=0$. The value of $\dfrac{bd}{ac}$ is:
The equation of the plane $P_1$ parallel to line $L: \frac{x-1}{2}=\frac{y-0}{3}=\frac{z-1}{1}$, at distance 6 from the intersection of $L$ with plane $P: 2x+3y+z-18=0$, and having maximum distance from $Q(5,4,-4)$, is $ax+by+cz+d=0$. The value of $\dfrac{bd}{ac}$ is:
Let $\gamma\in\mathbb{R}$ such that $L_1: \frac{x+1}{11}=\frac{y+2}{21}=\frac{z+3}{29}$ and $L_2: \frac{x+3}{16}=\frac{y+2}{11}=\frac{z+4}{\gamma}$ intersect at $R_1$. Match P)$\gamma$; Q)unit normal $\hat{n}$; R)$\overrightarrow{OR_1}$; S)$\overrightarrow{OR_1}\cdot\hat{n}$ with List-II: 1)$-\hat{i}-\hat{j}+\hat{k}$; 2)$\frac{3}{2}$; 3)$1$; 4)$\frac{1}{\sqrt{6}}\hat{i}-\frac{2}{\sqrt{6}}\hat{j}+\frac{1}{\sqrt{6}}\hat{k}$; 5)$\frac{2}{3}$
There is a plane $P$ passing through the line $\dfrac{x+1}{2}=\dfrac{y-1}{1}=\dfrac{z+3}{2}$ and parallel to the $x$-axis. Let $\vec{v}$ be a vector parallel to plane $P$ such that the angle between $\vec{v}$ and $\vec{u}=\hat{i}+\hat{j}+\hat{k}$ is least. There is a circle lying on plane $P$ with centre $C(0,0,-5)$ and radius $\sqrt{10}$. A line $L$ on plane $P$ is tangent to the circle at a point $Q(x,y,z)$ with the least possible value of $z$. Then which of the following is/are true?
Let $\vec{a},\vec{b},\vec{c},\vec{d}$ be position vectors of $A,B,C,D$ with $|\vec{a}|=1$, $|\vec{b}|=2$, $|\vec{c}|=3$, $|\vec{d}|=4$, $(\vec{a}\times\vec{b})\cdot(\vec{c}\times\vec{d})=24$, $\vec{a}\cdot\vec{c}=\frac{3}{2}$, $\vec{b}\cdot\vec{c}>0$. Area of $\triangle ABC=\frac{1}{4}(2\alpha+\beta\sqrt{3})$ and area of $\triangle BCD=\frac{1}{2}(m-n\sqrt{3})$ where $\alpha,\beta,m,n\in\mathbb{N}$. Match P)$\alpha$, Q)$\beta$, R)$m$, S)$n$ with 1)1, 2)3, 3)4, 4)9.
There is a plane $P$ passing through the line $\dfrac{x+1}{2}=\dfrac{y-1}{1}=\dfrac{z+3}{2}$ and parallel to the $x$-axis. Let $\vec{v}$ be a vector parallel to plane $P$ such that the angle between $\vec{v}$ and $\vec{u}=\hat{i}+\hat{j}+\hat{k}$ is least. There is a circle lying on plane $P$ with centre $C(0,0,-5)$ and radius $\sqrt{10}$. A line $L$ on plane $P$ is tangent to the circle at a point $Q(x,y,z)$ with the least possible value of $z$. Then which of the following is/are true?
Let $\vec{a},\vec{b},\vec{c},\vec{d}$ be position vectors of $A,B,C,D$ with $|\vec{a}|=1$, $|\vec{b}|=2$, $|\vec{c}|=3$, $|\vec{d}|=4$, $(\vec{a}\times\vec{b})\cdot(\vec{c}\times\vec{d})=24$, $\vec{a}\cdot\vec{c}=\frac{3}{2}$, $\vec{b}\cdot\vec{c}>0$. Area of $\triangle ABC=\frac{1}{4}(2\alpha+\beta\sqrt{3})$ and area of $\triangle BCD=\frac{1}{2}(m-n\sqrt{3})$ where $\alpha,\beta,m,n\in\mathbb{N}$. Match P)$\alpha$, Q)$\beta$, R)$m$, S)$n$ with 1)1, 2)3, 3)4, 4)9.
Let $\gamma\in\mathbb{R}$ such that $L_1: \frac{x+1}{11}=\frac{y+2}{21}=\frac{z+3}{29}$ and $L_2: \frac{x+3}{16}=\frac{y+2}{11}=\frac{z+4}{\gamma}$ intersect at $R_1$. Match P)$\gamma$; Q)unit normal $\hat{n}$; R)$\overrightarrow{OR_1}$; S)$\overrightarrow{OR_1}\cdot\hat{n}$ with List-II: 1)$-\hat{i}-\hat{j}+\hat{k}$; 2)$\frac{3}{2}$; 3)$1$; 4)$\frac{1}{\sqrt{6}}\hat{i}-\frac{2}{\sqrt{6}}\hat{j}+\frac{1}{\sqrt{6}}\hat{k}$; 5)$\frac{2}{3}$
Let A(x1, y1, z1), B(x2, y2, z2), C(x3, y3, z3), D(x4, y4, z4) be the vertices of a tetrahedron. If E is the centroid of face BCD and G is the centroid of ABCD, then find the value of K such that AG = K(AE).
The equation of plane containing line AC and at a maximum distance from B isGiven: A = 3i + 4j, C = 4i + 3j, B = 7i + 7j
The direction ratios of normal to the plane through the points (0, –1, 0) and (0, 0, 1) and making an angle \(\pi/4\) with the plane \(y - z + 5 = 0\) are:
If a line makes angles α, β and γ with the coordinate axes, then:
The equation of the straight line through the origin parallel to the line $(b+c)x + (c+a)y + (a+b)z = k = (b-c)x + (c-a)y + (a-b)z$ is:
The locus of intersection of locus of $P$ with $2x + y + z = 2$ is:
If the line $\frac{x-2}{-1} = \frac{y+2}{1} = \frac{z+k^2-1}{4}$ is one of the angle bisector of the lines $\frac{x}{1} = \frac{y}{-2} = \frac{z}{3}$ and $\frac{x}{-2} = \frac{y}{3} = \frac{z}{1}$, then the value of $k$ is/are:
Plane $P$ through $\frac{x-1}{1}=\frac{y-2}{-3}=\frac{z+5}{7}$ and $(2,4,-3)$. Image of $(-1,3,4)$ in $P$ is $(\alpha,\beta,\gamma)$. Then $\alpha+\beta+\gamma$ is equal to
The equations of the planes through the origin which are parallel to the line $\frac{x - 1}{2} = \frac{y + 3}{-1} = \frac{z + 1}{-2}$ and at a distance $5/3$ from it are:
A tetrahedron has vertices at \(O(0, 0, 0)\), \(A(1, 2, 1)\), \(B(2, 1, 3)\) and \(C(-1, 1, 2)\). Then, the angle between the faces \(OAB\) and \(ABC\) will be
A line makes the same angle θ with X-axis and Z-axis. If the angle β, which it makes with Y-axis, is such that \(\sin 2β = 3 \sin 2θ\), then the value of \(\cos^2 θ\) is
Let $Q(a,b,c)$ be the image of the point $P(3,2,1)$ in the line $\dfrac{x-1}{1}=\dfrac{y}{2}=\dfrac{z-1}{1}$. Then the distance of $Q$ from the line $\dfrac{x-9}{3}=\dfrac{y-9}{1}=\dfrac{z-5}{-2}$ is
The equation of planes bisecting the angle between the planes $2x - y + 2z + 3 = 0$ and $3x - 2y + 6z + 8 = 0$ is/are:
Let $A$ be the point $(1, 2, 3)$ and $B$ be a point on the line $\frac{x-1}{2} = \frac{y+1}{2} = \frac{z-3}{2} = k$. The value of $k$ such that line $AB$ is perpendicular to the plane $4x + 9y - 18z = 6$ is
The value of $\sin^{-1} \sin \lambda$ is equal to:
Let P be the plane, passing through the point $(1, -1, -5)$ and perpendicular to the line joining the points $(4, 1, -3)$ and $(2, 4, 3)$. Then the distance of P from the point $(3, -2, 2)$ is
Projection of line $\frac{x+1}{2} = \frac{y+1}{-1} = \frac{z+3}{4}$ on the plane $x + 2y + z = 6$ has equation:
If a point $P(\alpha, \beta, \gamma)$ satisfying $(\alpha\ \beta\ \gamma)\begin{pmatrix}2&10&8\\9&3&8\\8&4&8\end{pmatrix} = (0\ 0\ 0)$ lies on the plane $2x + 4y + 3z = 5$, then $6\alpha + 9\beta + 7\gamma$ is equal to:
The vector equation of the plane through the point \(\vec{i} + 2\vec{j} - \vec{k}\) and perpendicular to the line of intersection of the planes \(\vec{r} \cdot (3\vec{i} - \vec{j} + \vec{k}) = 1\) and \(\vec{r} \cdot (\vec{i} + 4\vec{j} - 2\vec{k}) = 2\), is
A perpendicular is drawn from a point on the line $\frac{x-1}{2} = \frac{y-1}{-1} = \frac{z}{-1}$ to the plane $x + y + z = 3$ such that the foot of the perpendicular $Q$ also lies on the plane $x + y - z = 3$. Then the coordinates of $Q$ are
If (a, b, c) is the image of the point (1, 2, -3) in the line \(\frac{x+1}{2} = \frac{y-3}{-2} = \frac{z}{-1}\), then a + b + c 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
The line passing through the points (5, 1, a) and (3, b, 1) crosses the yz-plane at the point \(\left(0, \dfrac{17}{2}, \dfrac{-13}{2}\right)\). Then
The locus of intersection of locus of $P$ and the plane $x + y + z = 2$
The equation of line intersecting and perpendicular to the line $\frac{x}{2} = \frac{y-2}{3} = \frac{z-3}{4}$ and passing through $(-2, -5, 7)$ is :
The equation of the plane containing the line \(\frac{x-4}{1} = \frac{y-7}{5} = \frac{z-4}{4}\) and passing through the point (3, 2, 0) is:
If a variable point $P$ moves such that the line passing through $P$ and $Q(0, 0, 2)$ makes an angle $60°$ with $z$-axis, then locus of $P$ is:
The equation of the plane containing the line \(\dfrac{x - x_1}{l} = \dfrac{y - y_1}{m} = \dfrac{z - z_1}{n}\) is \(a(x - x_1) + b(y - y_1) + c(z - z_1) = 0\), where
The radius of the circle in which the sphere \(x^2 + y^2 + z^2 + 2x - 2y - 4z - 19 = 0\) is cut by the plane \(x + 2y + 2z + 7 = 0\) is
Line \(PQ: \dfrac{x+1}{4} = \dfrac{y-2}{-2} = \dfrac{z+3}{6}\). A point \(R\) satisfies \(2x - 2y + 3z + 1 = 0\). For \(|PQ - QR|\) to be maximum, \(P\), \(Q\), \(R\) must be collinear. Find \(x_0 + y_0 + z_0\).
A perpendicular is drawn from a point $(1, 6, 3)$ to the line $\frac{x}{1} = \frac{y-2}{2} = \frac{z-3}{-3}$. What will be coordinates of the foot of perpendicular:
The foot of perpendicular of the point $(2, 0, 5)$ on the line $\frac{x+1}{2} = \frac{y-1}{5} = \frac{z+1}{-1}$ is $(\alpha, \beta, \gamma)$. Then which of the following is NOT correct?
A ray of light is coming along the line $\frac{x-2}{3} = \frac{y-1}{4} = \frac{z-6}{5}$ and strikes the plane mirror kept along the plane through the points $(2, 1, 0)$, $(5, 0, 1)$ and $(4, 1, 1)$. Then the equation of reflected ray is:
The distance of the point $(7, -3, -4)$ from the plane passing through the points $(2, -3, 1)$, $(-1, 1, -2)$ and $(3, -4, 2)$ is: