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
47
votes
7 answers

How to calculate the intersection of two planes?

How to calculate the intersection of two planes ? These are the planes and the result is gonna be a line in $\Bbb R^3$: $x + 2y + z - 1 = 0$ $2x + 3y - 2z + 2 = 0$
user1111261
  • 1,149
38
votes
17 answers

Get the equation of a circle when given 3 points

Get the equation of a circle through the points $(1,1), (2,4), (5,3) $. I can solve this by simply drawing it, but is there a way of solving it (easily) without having to draw?
JohnPhteven
  • 2,007
15
votes
2 answers

How to find whether equation of angle bisector represents the obtuse or acute angle bisector of two given straight lines?

Two lines: $a_1x + b_1y + c_1 = 0$ and $a_2x + b_2y + c_2 = 0$ are given. I know that the equation of its bisectors is ${a_1x + b_1y + c_1 \over \sqrt{(a_1^2 + b_1^2)}} = \pm {a_2x + b_2y + c_2 \over\sqrt{ (a_2^2 + b_2^2)}}$ But I intend to find…
Matt
  • 1,150
11
votes
2 answers

The intersections of 2 circles

Lets consider the following (random) question: Find the intersections of the circles $c_1: x^2+y^2=25$ and $c_2: (x-2)^2 + (y-3)^2=9$ In order to solve this we can do $c_2-c_1$, which leaves us with $y=-\dfrac{4}{6}x+\dfrac{29}{6}$. If we then…
JohnPhteven
  • 2,007
9
votes
1 answer

Is this solution legal?

Let $M(1,-1)$ be a point in a plane. Find its distance from a line given by $x+2y-4=0$. Later on I found a formula: $$d=\frac{\left | Ax_{0}+Bx_{0}+C \right | }{\sqrt{A^2+B^2}}$$ But I did it somehow without using it. Like this: The distance…
tyr
  • 618
8
votes
4 answers

Given two points, find another point a perpendicular distance away from the midpoint

I am a computer programmer and need to find the x and y coordinate of a point that is a defined perpendicular distance from a midpoint. For reference, I have tried to attached an image for reference. X1, Y1, D, X2, Y2 will be given. I need to find…
tpdietz
  • 183
8
votes
2 answers

Finding shortest distance from point to plane

I need you guys to check my homework question out if I'm wrong or not... Given point $(1,4,1)$ in need to find the shortest distance between this and the plane $2x_1 - x_2 + x_3 = 5$. So firstly, I found the normal $n = \left(…
meiryo
  • 875
7
votes
1 answer

Prove that 1/x is a hyperbola

Prove that 1/x is a hyperbola with foci given by $(\sqrt2,\sqrt2)$ and $(-\sqrt2,-\sqrt2)$. The idea is to use ONLY the definition of a hyperbola, that is: Let $F_1$ and $F_2$ be two given points. A hyperbola $H$ is the set of points in the…
Math Guy
  • 364
6
votes
1 answer

Does a square have an equation?

can you model a square in an equation ? like a circle for example $r^2 = x^2 + y^2$ and lets say we have a square with: centered at $(3,3)$ $2 \leq x \leq 4$ and $2 \leq y\leq 4$ can we somehow make an equation for that square ?
AnarKi
  • 267
6
votes
2 answers

Generalizing the hardest question on the practice math GRE

The most-missed question on the Math GRE is the following: How many times does $x^{12}$ intersect $e^x$? Because I told you it was hard, you probably realized it was a trick and got the right answer; or you were among the ~25% who got it right on…
Brian Rushton
  • 13,255
  • 11
  • 59
  • 93
6
votes
4 answers

Find the intersection points of two circles

Find the intersection points of the circles $$k_1:(x-4)^2+(y-1)^2=9\\k_2:(x-8)^2+(y+4)^2=100$$ The intersections point (if they exist) will satisfy the equations of both the circles, so we can find their coordinates by solving the system…
kormoran
  • 2,963
6
votes
2 answers

Finding the z value on a plane with x,y values

so I have the x,y,z value for 3 points to define a plane in 3d space. I need to find the z value of an arbitrary point given the x,y. I can sort of see some ways to calculate this, but they seem like they might be doing a lot of extra steps. I…
6
votes
2 answers

Area of square under a curve.

A square having sides parallel to the coordinate axes is inscribed in the region. {$(x,y):x,y>0:y\le -x^3+3x$}. If the area of the square is written as $A^{1/3}+B^{1/3}$ square units where $A,B\in \Bbb Z$ and $A>B$, then find (i)$\sqrt{A-B}$ …
6
votes
2 answers

What formulas should I use to craft a procedural paisley?

I would like to create procedural paisleys. For my purposes a paisley is a curled teardrop shape (google image search) composed of multiple shells. I think it best to exclude the ones that have spiral tails. My first attempt was to use (piecewise)…
6
votes
4 answers

Prove that a point can be found which is at the same distance from each of the four points$\ldots$

Prove that a point can be found which is at the same distance from each of the four points $\bigg(am_1,\dfrac{a}{m_1}\bigg),\bigg(am_2,\dfrac{a}{m_2}\bigg),\bigg(am_3,\dfrac{a}{m_3}\bigg)$ and $\bigg(am_1m_2m_3,\dfrac{a}{m_1m_2m_3}\bigg)$ My…
Swadhin
  • 1,381
1
2 3
68 69