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.

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Proof of geometric perspective?

So I'm struggling to draw squares in perspective. I came across this technique where the method used is by dividing in half the angle made by the vertices of the lowest horizontal line parallel to horizon and the lines connecting it to the vanishing…
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What is the intersection point of the equations : $4x+2y+1=0$ and $12x+4y+8=0$?

What is the specific $x$ value and $y$ value for this set of equation? Since these lines are parallel I am not able to find the $x$ and $y$ values. But does that imply that this equations are solution less? When I try method of elimination it…
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Line of intersection of two planes in parametric form

You are given two planes in parametric form : \begin{eqnarray*} S_{1} : \begin{pmatrix} x_{1}\\ x_{2}\\ x_{3} \end{pmatrix} = \begin{pmatrix} 0\\ 0\\ 0 \end{pmatrix} + u_1 \begin{pmatrix} 1\\ 2\\ 0 \end{pmatrix} + v_1…
begbeg
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Values of constant $k$ for which line $2x+ky =-k$ passes within $1$ unit of origin.

The problem is taken from the chap. 1.1 of the book titled : Calculus Problems for the new century, by Robert Fraga. The equation $2x+ky =-k$ is the equation of a line. Determine the values of the constant $k$, if any, for which the line passes…
jiten
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How to find reflection point over the line?

The $P$ point is $(2,-1,3)$ and the line is $$l: \begin{cases} x-y-z=0,\\ x+y-2x=0 \end{cases}.$$ How to compute the reflection point $P$ over the line $l$? What is the general formula for the line going through $P$ being perpendicular to $l$?
zorro47
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Show a polar equation describes a cylinder

I have to show that $2r+r\cos\theta =1$ describes a cylinder. I try moving the equation to cartesian coordinates and I get$\ 3x^2+4y^2-2x=1$, after that I don't know what to do, any help would be appreciated.
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Finding the perpendicular line of a given line.

How can I find the line that contains the point $\ (0,2,1) $ and intersect the line $\ (2t,1-t,2+t) $ in $\ 90 $ degrees Maybe since the direction vector of the given line is $\ (2,-1,1) $ and the the direction vector of the line I look for is…
bm1125
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5 numbers are enough to give a line

My question is very elementary; I just want to ask if it is widely known (probably yes) and whether this is written in textbooks (where). A line in the 3-dimensional space is usually given either by two points or by a point and a vector; in total 6…
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Finding a line with the following criteria

Find the line that goes through $\ (0,1,2) $, is parallel to the plane $\ x+y+z-2=0 $, and is perpendicular to $\ r(t) = (1+t,1-t,2t) $. I understand that the line is perpendicular to the vectors $\ (1,-1,2)$ and $(1,1,1) $, but I'd like some…
bm1125
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How to find equation of line intersecting with two given lines and parallel to the given plane

We have given two lines $a$ and $b$ and a plane $\sum$. We are asked to find equation of a line which is intersecting with the lines $a$ and $b$ and is parallel to the given plane $\sum$. $$a: \frac{x}{2} = \frac{y-1}{1} = \frac{z-1}{2} \\b:…
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Line $y=c$ where $c$ is a constant intersects $y=x^2$ with part of it reflected at $y=1$ at $A, B, C, D$ where $AB=BC=CD$. What is $AB$?

An M-shaped curve is created by graphing the parabola $y=x^2$ in the coordinate plane, and then reflecting the part of the parabola that is above the line $y=1$ across the line $y=1$. There is a horizontal line that intersects the M-shaped curve at…
Max0815
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The number of lattice points bound by the x and y axes, and the line $3x-y=24$.

The right triangle bound by the x and y axes and the line $3x-y=6$ contains 2 lattice points in its interior. How many lattice points will be contained in the interior of a triangle bound by the x and y axes and the line $3x-y=24$? So I…
Max0815
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A tricky question on circles - Loney Exercise XVIII, problem 14

I am brushing up some plane and solid analytic geometry before taking a course on multivariable calculus. I am deriving important results and solving through the book, Co-ordinate Geometry by SL Loney. I am stuck on a question in circles, I feel the…
Quasar
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Intuitive questions about the shape of an $\ell_1$ ball in dimensions $n \geq 4$?

It is easy to intuitively see that the shape of a two-dimensional $\ell_1$ ball is a sort of diamond, and that the three-dimensional generalization of it will be a similar shape, i.e., a shape where if you slice into it along any of the planes…
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How to calculate ray

In ray-tracing technique critical point is to calculate rays which came out from eye $E$ to target $T$ through pixel $P_{ij}$ on viewport. The "viewport" is represented as rectangle divided to square pixels - this rectangle is perpendicular to line…