3D Geometry Questions (578)

Consider the set of eight vectors $V=\{a\hat{i}+b\hat{j}+c\hat{k}: a,b,c\in\{-1,1\}\}$. The number of ways three non-coplanar vectors can be chosen from $V$ equals
Volume of parallelopiped determined by vectors $\vec{a},\vec{b},\vec{c}$ is 5. Then volume determined by $3(\vec{a}+\vec{b})$, $(\vec{b}+\vec{c})$ and $2(\vec{c}+\vec{a})$ 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
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
Let $\vec{a}$, $\vec{b}$, $\vec{c}$ be three non-zero vectors satisfying $\vec{a}=\vec{b}\times\vec{c}+2\vec{b}$, where $|\vec{b}|=|\vec{c}|=2$ and $|\vec{a}|\leq4$. The sum of possible values of $|2\vec{a}+\vec{b}+\vec{c}|$ is
Let $L_1$, $L_2$ be two distinct lines such that $L_1$ and $L_2$ are not perpendicular. Let $P$ be a plane such that $L_1$ and $L_2$ are not perpendicular to $P$. Let $L_3$ and $L_4$ be projections of $L_1$ and $L_2$ on plane $P$ respectively. If $\theta$ be angle between $L_3$ and $L_4$ then $\theta$ CANNOT be equal to
Consider lines $L_1:\{3\sqrt3x=4\sin\theta\,y+(2\sqrt{\sin\theta}-3)\,3\sqrt3,\;3\sqrt3z=(2\sqrt{\sin\theta}-3)y+3\sqrt3\sin\theta\}$ and $L_2:\{\sqrt3x=-2\sqrt{\cos\theta}\,y+\sqrt3(3-2\sqrt{\cos\theta}),\;\sqrt3z=(3-2\sqrt{\cos\theta})y+\sqrt3\cos\theta\}$. If $L_1\perp L_2$ then
Minimum value of the expression $(a-b)^2 + \left(4\sqrt{1+a^2} + 2\sqrt{2b-b^2}\right)^2$ is
Equation of plane containing the line $\dfrac{x-1}{2}=\dfrac{y-2}{3}=\dfrac{z-3}{4}$ at minimum possible distance from $(-1,-3,1)$ is
A line through $(2,-2,5)$ with direction $(1,-3,2)$ meets the plane $2x-3y+4z=163$ at $P$ and the $YZ$-plane at $Q$. If $PQ = a\sqrt{b}$ where $a>3$, find $a+b$.
Let $\vec{a}=3\hat i-4\hat j+5\hat k$, $\vec{b}=\hat i+2\hat j-2\hat k$, $\vec{c}=5\hat i-12\hat j-13\hat k$. If $\vec{r}\times\vec{b}=\vec{b}\times(\vec{a}-\vec{c})$ and $\vec{r}\cdot(\vec{a}+\vec{c})=0$, then $|\vec{r}-36\vec{b}|^2$ is
The distance between the line $\vec{r}=2\hat{i}-2\hat{j}+3\hat{k}+\lambda(\hat{i}-\hat{j}+4\hat{k})$ and the plane $\vec{r}\cdot(\hat{i}+5\hat{j}+\hat{k})=5$ is
According to direction cosines, we know that \(\cos^2\alpha + \cos^2\beta + \cos^2\gamma = 1\). Given that \(\alpha = \dfrac{\pi}{3}\) and \(\beta = \dfrac{\pi}{4}\), find the value of \(\gamma\) (in degrees).
A line through $(2,-2,5)$ with direction $(1,-3,2)$ meets the plane $2x-3y+4z=163$ at $P$ and the $YZ$-plane at $Q$. If $PQ = a\sqrt{b}$ where $a>3$, find $a+b$.
The general coordinates of a point R which divides the line joining A(3, –2, 4) and B(1, 1, 1) in the ratio μ : 1 are \(\left(\dfrac{\mu+3}{\mu+1},\ \dfrac{\mu-2}{\mu+1},\ \dfrac{\mu+4}{\mu+1}\right)\). If C(–1, 4, –2) lies on the line AB, then the value of |μ| is:
The shortest distance between the z-axis and the line \(x + y + 2z - 3 = 0 = 2x + 3y + 4z - 4\) is
If the equation of the plane through $(-1,2,0)$ and parallel to 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 $a+b+c$ is
Let $(\alpha,\beta,\gamma)$ be the mirror image of $(1,-2,3)$ in the line $\dfrac{x+1}{2}=\dfrac{y-3}{4}=\dfrac{z+2}{3}$. Then $2\alpha+4\beta+3\gamma+2=$
A plane passing through \((1, 1, 1)\) cuts positive direction of co-ordinate axes at \(A\), \(B\) and \(C\), then the minimum value of the volume of tetrahedron \(OABC\)
Minimum value of the expression $(a-b)^2 + \left(4\sqrt{1+a^2} + 2\sqrt{2b-b^2}\right)^2$ is
The shortest distance between lines $\vec{r}=(6\hat{i}+2\hat{j}+2\hat{k})+\lambda(\hat{i}-2\hat{j}+2\hat{k})$ and $\vec{r}=(-4\hat{i}-\hat{k})+\mu(3\hat{i}-2\hat{j}-2\hat{k})$ is
The vector equation of the plane through the line of intersection of the planes $x+y+z=1$ and $2x+3y+4z=5$ which is perpendicular to the plane $x-y+z=0$ is
Let $OA$, $OB$, $OC$ be coterminous edges of a cuboid. If $l,m,n$ be the shortest distance between the sides $OA$, $OB$, $OC$ and their respective skew body diagonals to them, then find $\dfrac{\left(\frac{1}{l^2}+\frac{1}{m^2}+\frac{1}{n^2}\right)}{\left(\frac{1}{OA^2}+\frac{1}{OB^2}+\frac{1}{OC^2}\right)}$
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
Three mutually perpendicular lines have direction ratios $(1,1,0)$, $(1,0,1)$, $(0,1,1)$ and pass through $(1,0,1)$, $(1,1,0)$, $(0,1,1)$ respectively. The volume of the tetrahedron formed by them and the plane $x+y+z=1$ is $V$. Find $16V^2$.
The perpendicular distance of point $(2,0,-3)$ from the line which passes through $(0,2,-4)$ and perpendicular to the lines $\vec{r}=(-3\hat{i}+2\hat{k})+\lambda(2\hat{i}+3\hat{j}+5\hat{k})$ and $\vec{r}=(\hat{i}-2\hat{j}+\hat{k})+\mu(-\hat{i}+3\hat{j}+2\hat{k})$
Volume of parallelopiped determined by vectors $\vec{a},\vec{b},\vec{c}$ is 5. Then volume determined by $3(\vec{a}+\vec{b})$, $(\vec{b}+\vec{c})$ and $2(\vec{c}+\vec{a})$ is
It is given that lines L_1: \frac{x+1}{2} = \frac{y-2}{-1} = \frac{z-1}{1} and L_2: \frac{x+2}{a} = \frac{y+1}{5-a} = \frac{z+1}{1} are coplanar. Find the value of a.