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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rotational of polynomials

first of all it is well known that if we rotate (x,y) coordinate by some angle (let's say by A) then new image(x',y') will be related to (x,y) by the following formula x' = x*cosA - y*sin A and y' = x *sin A + y*cos A, now i have a question…
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Finding coordinates of 4th point in a quadilateral

A(1,5), B(4,0), C(-3,-5) are three vertices of a parallelogram ABCD. Find the coordinates of D, the fourth vertex of the parallelogram *What I've Done:*I've created the structure on a number plane. I was wondering do you have to find the…
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Equation of circumscribing circle

Show that a cyclic quadrilateral is formed by the lines $5x+3y=9$, $x=3y$, $2x=y$ and $x+4y+2=0$ taken in order. Find the equation of the circumscribing circle. How do i go about it?
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How to sketch $f(x)= |2x-1|-|1+3x|$

How would you sketch $f(x)= |2x-1|-|1+3x|$? And how would you work out how to sketch it? Please help!
Tomp
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about projection

Let $L$ be the line in $\Bbb R^3$ containing the point $A (0,1,1)$. Specifically, let $L = \{t[0,0,1]+[0,1,1]\mid t\in\Bbb R\}$. Let $U=[1,-1,0]$ The question is to find the point on the line which is closet to the point $U$. And here is the…
Jing
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Given middlepoints of a sides of triangle, find vertices

If $(2, 1)$, $(3, 3)$ and $(6, 2)$ are the middlepoints of a sides of a triangle, what are the coordinates of a vertices of a triangle? This part of the book deals with midpoints, with formula: $$M_x = \frac{x_1 + \lambda \cdot x_2}{1 +…
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Problem regarding lines (Analytic Geometry)

Here is the problem: The base of a triangle has a fixed position and its length is constant and measures a. The difference of the squares of the other two sides is constant and measures $b^2$. Prove that the geometric space is a line. Honestly, I…
OFRBG
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How to find a perpendicular vector

After thinking longing i can't figure it out no matter what.. So i have 3d line starts (0,0,0) and ends (3.5,3.5,2.5) so therefore has length of about 5. Now how do i find out vector that is completely perpendicular to any vector like this one…
Techsin
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Find the slope or angle to the horizontal of an internal common tangent of two circles

I'm looking for a general (hopefully computationally efficient) algorithm for the problem in the title, given the centers and radii of the circles in question. If it matters, I am always looking for the internal common tangent for which the…
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Can lines be defined with its slope and a point on it definitely?

If I get the slope of a line, and one point that is on it, then, are they define exactly ONE line? The point–slope form of linear equations ($y - y_1 = m( x - x_1 )$) need only the slope and the coordinates of that given point. And this equation…
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Selector function $f_\mathbb{P}$ for any $\mathbb{P} \subseteq \mathbb{R}^n$.

Here, I explain the problem for the case of $\mathbb{R}^2$. But, eventually we could extend this to any number of dimensions. Consider any $\mathbb{P} \subseteq \mathbb{R}^2$. I want to make a selector function $f_\mathbb{P}$ such that when we write…
Truth-seek
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A Proof Problem about conical surface on Analytic Geometry

A necessary definition $F(x,y,z)$ is called a homogeneous function of degree $n$ ($n$ is an integer) if $F(tx,ty,tz)=t^nF(x,y,z)$ holds for any nonzero real number t,and any possible x , y, z. In this case, $F(x,y,z)=0$ is said to be a homogeneous…
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The points $B = (3, 1)$ and $C = (-2, 5)$ are the vertices of an equilateral triangle $ABC$. Calculate the area and perimeter of this triangle.

I encountered a problem while solving this task. It is an equilateral triangle so $\vert AB \vert = \vert AC \vert = \vert BC \vert$. I then calculated the length of the segment $\vert BC \vert$ $$\vert AB \vert = \sqrt{(X_B-X_A)^2+(Y_B-Y_A)^2}$$ So…
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Signed distance from vector direction and signed offset from vector start

Let v be vector from (0,0) to A and B be any point. How to calcule the signed distance to the direction of v and sign be lift or right looking forward aligned to the vector. And signed offset from 0,0 to closest point to B on v's direction?
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How does one calculate the simpson line algebraic?

I would like to apply this theorem to a triangle on the unitcircle: Let P be a point on the unit circumcircle of triangle ABC. The equation of its Simson line is: $$2abc\overline{z}-2pz+p^2+(a+b+c)p-(bc+ca+ab)-\frac{abc}{p}=0 $$ Ive tried with…
Henk
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