Questions tagged [analytic-geometry]

Questions on the use of algebraic techniques for proving geometric facts. Analytic Geometry is a branch of algebra that is used to model geometric objects - points, (straight) lines, and circles being the most basic of these. It is concerned with defining and representing geometrical shapes in a numerical way.

Analytic geometry, also called coordinate geometry, mathematical subject in which algebraic symbolism and methods are used to represent and solve problems in geometry.

The importance of analytic geometry is that it establishes a correspondence between geometric curves and algebraic equations. This correspondence makes it possible to reformulate problems in geometry as equivalent problems in algebra, and vice versa; the methods of either subject can then be used to solve problems in the other.

Analytic geometry was introduced by René Descartes in $1637$ and was of fundamental importance in the development of the calculus by Sir Isaac Newton and G. W. Leibniz in the late $17^{th}$ cent. More recently it has served as the basis for the modern development and exploitation of algebraic geometry.

6689 questions
1
vote
1 answer

Can you help me find this unit vector?

The vectors $a = (1,1,1)$ and $b = (−1, −1, −1)$ are given. Determine the unit vector $c$ such that $\angle (a, c) = \frac \pi 6$ and that the area of ​​the parallelogram constructed over the vectors $b$ and $c$ is equal to $\sqrt2.$ So I tried…
1
vote
1 answer

Find an ellipse from two points and the tangent at a third point

I am searching an ellipse in the form $\frac{\left(x - x_\circ\right)^2}{a^2} + \tfrac{\left(y - y_\circ\right)^2}{b^2} = 1$ (its axis parallel to the coordinate axes). What I know are three points, and for one of them I additionally know the…
ccprog
  • 121
1
vote
1 answer

Question regarding analytic geometry

Problem: Given a convex polygon with $N$ sides, say $[A_1A_2...A_N]$. We know all the coordinates of the vertices of the polygon $A_1=(x_1,y_1)$, $A_2=(x_2,y_2)$, ..., $A_N=(x_N,y_N)$. We will move all sides of the polygon, for $d$ units, parallel…
1
vote
1 answer

A line and a plane in 3 dimensions

Line L is defined as point P(3, 2, -2) with a directional vector v <1, -1, 2>. Plane S: A $(1, 2, 1)$, B $(2, -1, 2)$, C $(0, -2, 1)$ a) When t = 2, how far away is the particle's position located from the plane? b) If the source of light is shines…
1
vote
1 answer

Analytic Geometry question on orthogonal lines

I am solving some past exam questions for a japanese university entrance exam and got stuck in this question: In this pyramid, each side of the square $ABCD$ equals $2a$, also the height $OH = a$, $M$ is a mid point on $AB$. Finally $AE$ and $OB$…
1
vote
0 answers

6 arbitrary vectors emanate from a point, which is also the center of a cube. Can they go through one side each if you rotate the cube?

I don't come from a pure mathematics background, so bear with me. I was thinking about the movie/tv show Stargate, with this picture in particular: James Spader drawing something like what I'm talking about.. It represents how the Stargate uses 6…
1
vote
1 answer

Locus of points where tangents drawn on hyperbola make angle 45

Find the locus of points where a pair tangents drawn on the hyperbola $x^2 - y^2 = a^2 $ enclose an angle of $45$ degrees. This is what I've done so far. $\theta$ between tangents is $45$ so $\lvert \frac{m_2-m_1}{1+m_1m_2)}\rvert = tan45 =1$…
1
vote
1 answer

The equation of a sphere tangent to two planes

The center of a sphere belongs to the line $$d : {{x-1}\over3} = {{y}\over 2} = {{z+2}\over-2} $$ Find the equation of the sphere if the planes $$ (P):z+3=0$$ $$ (Q) :3x-4z-33=0 $$ are tangent to the sphere. My solution: from the parametric…
1
vote
3 answers

Normal between two lines

$$l_1:x=(-1,1,2)+t(1,-3,-2)$$ $$l_2:y=(1,1,1)+s(-2,6,-4)$$ Q: Find the equation of plane passing through $l_1$ and $l_2$. My teacher wrote answer like this: Since they're parallel, choose vector $u=(1,-3,-2)$ and choose normal vector…
SaintRS
  • 55
  • 6
1
vote
0 answers

Finding intersections of a cubic polynomial with a hyper sphere

I am trying to determine conditions under which three surfaces in $\mathbb{R}^n$ intersect. The first two surfaces are an $n$-plane and an $n$-sphere: $$\sum_{j=1}^n x_j = C$$ $$\sum_{j=1}^n x_j^2 = R^2$$ These intersect in an $(n-1)$-sphere so long…
1
vote
1 answer

Why does this shortcut to the section formula work?

If a straight line $ax+by+c=0$ divides the line segment joining the points $A(x_1,y_1)$ and $B(x_2,y_2)$ in the ratio $k:1$, the standard way of finding $k$ is to use the section formula and input the point of intersection in the equation of the…
1
vote
3 answers

Quadratic surfaces and intersection curves

You are given a second order surface $Ax^2+By^2+Cz^2=α$ and a plane $x+z=β$. Determine the type of the surface and the type of the curve at the intersection of the surface and the plane. Basically, I need to write a program, that will do task,…
Prox
  • 77
  • 6
1
vote
0 answers

Determine the sets and give the the geometric description

We define \begin{equation*}\mathbb{L}(a,b,c):=\left \{\begin{pmatrix}x\\ y\end{pmatrix}\in \mathbb{R}^2\mid ax+by=c\right \}\end{equation*} Determine $\mathbb{L}(1,1,0)$ and $\mathbb{L}(1,1,5)$ and give the the geometric description of these…
Mary Star
  • 13,956
1
vote
1 answer

Line equation - parametric and canonical

Let's say I have a line in R3: $$ l:\begin{cases} x-3y+3z=0\\ x+2y-2z=2 \end{cases} $$ How to change it to canonical and parametric equation?
TomDavies92
  • 1,215
  • 3
  • 13
  • 24
1
vote
2 answers

Local Diffeomorphism Theoerm

Is this correct for the local diffeomorphism theorem: A multivariable function $F(x_1, \cdots x_n)$ has a local diffeomorphism at a point $a = (a_1, \cdots a_n)$ if the determinant of the Jacobian matrix of $F$ at $a$ is not $0$. I.e $\det…
Kaish
  • 6,126