Questions tagged [vectors]
Use this tag for questions and problems involving vectors, e.g., in an Euclidean plane or space. More abstract questions, might better be tagged vector-spaces, linear-algebra, etc.
12,786 questions
0 votes
0 answers
33 views
Confusion regarding Tangent Basis
I am trying to get a better grasp of how to find the basis of the tangent space. Here is one example I worked on in hopes of practicing it: Consider the chart $(U,\psi)$, the manifold $\mathcal{M} = S^...
1 vote
0 answers
36 views
Standard error of a mean direction
I have $n$ unit vectors $\mathbf{x}_i \in \mathbb{R}^p$, whose (sample) mean direction is calculated with $$ \mu = \frac{\bar{\mathbf{x}}}{\bar{R}}, \text{ where } \bar{\mathbf{x}} = \frac{1}{n} \...
1 vote
2 answers
74 views
Determine the reflection line about which two points reflected will lie on two given lines respectively
You're given two lines in the $xy$ plane, let's say $ Line 1: a_1 x + b_1 y + c_1 = 0 $ and $ Line 2: a_2 x + b_2 y + c_2 = 0 $ In addition you're given two points $P = (p_1, p_2) $ and $Q = (q_1, q_2)...
2 votes
1 answer
93 views
Congruent triangle to a given one, with its vertices at specified distances from the original triangle vertices
You're given $\triangle ABC$ with known vertices in the $xy$ plane. The coordinates of $A,B,C$ are known. Now, given three distances $d_1, d_2, d_3$. You want to determine all congruent triangles $\...
0 votes
1 answer
48 views
How to adjust a vector so that both its net circulation and flux vanish?
I am working on a special type of problem which requires that a vector field derived from previously computed fields satisfy 2 constraints: $$1) \oint \textbf{V} \cdot \hat{\textbf{n}} ds = 0$$ $$2) \...
0 votes
0 answers
61 views
From two vectors I can get the cosine of their angle. But how to get that angle value (looking at quadrant) if they have more than two dimensions?
If I have two vectors $\vec{A}$ and $\vec{B}$ having two components I can calculate their scalar product. And then $\frac{\vec{A}\cdot\vec{B}}{||A|| \times ||B||}$ gives me their cosine, and through ...
0 votes
0 answers
77 views
When I consider a vector directly, or by its scalar product with $\vec{i}$ I don't receive the same angle measure
I believe that on an orthogonal coordinate system $(O,\vec{i},\vec{j})$, where $(O,\vec{i})$ would design the East, if someone gives me a single vector $\vec{R}(7.6, -3.4)$ it be convenient if I ...
1 vote
2 answers
109 views
Rotating a unit vector to another vector using two consecutive axes
Given a unit vector $u$ and another unit vector $v$, I want to rotate $u$ into $v$ in two stages. In the first stage, I rotate $u$ about a given axis $a_1$ (by an unknown angle) to produce a vector $...
1 vote
3 answers
88 views
Cartesian equation of X axis [closed]
In my school module it is written that the cartesian equation of $x$ axis is $$ \frac{x}{1}=\frac{y}{0}=\frac{z}{0} $$ Isn't dividing by zero not allowed? How have they written this equation
2 votes
2 answers
116 views
Rotate vector within plane by given angle
Let two 3D unit vectors $V, V'$ be given. Derive vector $W$ created by clockwise rotating $V'$ by angle $\theta'$ around the origin within the plane with normal proportional to $V \times V'$. I tried ...
0 votes
1 answer
32 views
Vector tangent to meridian
Let there be two different points $ \vec{p_1}, \vec{p_2}$ on a unit sphere. I need to get unit vector $\vec{t}$ at the point $\vec{p_1}$ tangent to the meridian (big circle) connecting these points. ...
0 votes
1 answer
55 views
Simple Algebraic Derivation of the Cross Product [duplicate]
I'm looking for a simple algebraic derivation of the cross product formula: $\vec{a} \times \vec{b} = \|\vec{a}\| \|\vec{b}\| \sin(\theta) \vec{n}$. I need the derivation to be simple, understandable ...
0 votes
1 answer
87 views
Bearing angle of great circular arc between Ottawa Canada, and Sarajevo, Bosnia
I have this problem that I have been working on today. I want to calculate the local direction of the great circle connecting Ottawa, Canada, and Sarajevo, Bosnia. I assume Earth is perfectly ...
0 votes
1 answer
60 views
Show that $pr_d(\overrightarrow{u}+\overrightarrow{v}) = pr_d\overrightarrow{u} + pr_d\overrightarrow{v}$
On a plane, give a line $d$ and the vectors $\overrightarrow{u}, \overrightarrow{v}\ne\overrightarrow{0}$ such that $\overrightarrow{u},\overrightarrow{v}$ are not perpendicular to the line $d$. Let $...
-2 votes
2 answers
83 views
I don't believe me, $\overrightarrow{Marc}(1.80\ m, 71\ kg, 56\ y.o.)$ I'm a vector of $\mathbb{R^3}$. But of $\mathbb{R^{+3}}$ or better. Am I right?
My beliefs: At school, I've seen all the time definition of vectors in $\mathbb{R^n}$. I've understood that if some are defined in $\mathbb{R^3}$ it means that: they all have three components all of ...