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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A question about affine spaces

Are there affine spaces that contain subsets that aren't closed to affine combinations of three points? This is a surprising question. I think that exists that kind of affine spaces,but I don't know what space should be considered as an…
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Find the magnitude of the acute angle between the lines $2y+3x=4$ and $x+y=5$.

Find the magnitude of the acute angle between the lines $2y+3x=4$ and $x+y=5$. I have no idea how to start the above equation. I try to draw the graph of $2y+3x=4$ and $x+y=5$ in the calculator but nothing show in the calculator. The formula…
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A problem about affine spaces

Let A be an affine space,dim(A)=4. P,Q are planes from A. If dir(P)!=dir(Q),then P and Q are disjoint. Is this proposition true or false? I know that two planes are parallel if they are disjoint only for an affine space B with dim(B)=2 or 3,but I…
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Tips to fix coordinates in analytic geometry.

I now know how useful analytic geometry can be in bashing geometry problems involving side lengths. Does anybody have any tips on how to fix coordinates to keep the solution from becoming too tedious? The solution doesn't have to be so tedious.…
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How to find the largest possible rectangle (by perimeter) on the following function?

It's been a while since I last tackled high-school math, and a friend asked me this question which I can't remember how to approach. I have the following: $ y = -x^2 + 5x $ Which produces an inverse parabola, intersecting with the $x$ axis on…
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prove that If and only if lines are perpendicular, the slopes are negative reciprocal.

I have to prove that If and only if lines are perpendicular, the slopes are negative reciprocal. I know to prove that if the lines are perpendicular,the slopes are negative reciprocal. But I dont know how to prove the opposite condition. Thanks.
NM2
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Given the points $A(3, 2)$ and $B(-5,-3)$, what is the product of the coordinates of the midpoint of $\overline{AB}$?

Given the points $A(3, 2)$ and $B(-5, -3)$, what is the product of the coordinates of the midpoint of $\overline{AB}$? Express your answer as a common fraction. I've tried to find the length of $\overline{AB}$ first by using Pythagorean Theorem, but…
space
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A problem in analytic geometry

Given points A and B, and a line p with its equation $p:\vec{r}=\vec{r_{p}}+t\vec{p}, t\in R$ such that $\vec{p}$ is not parallel to $\vec{AB}$. Find points C and D, as a function of $\vec{r_{a}}, \vec{r_{b}}, \vec{r_{p}}$ and $\vec{p}$ such that…
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Equation To The Pair Of Angle Bisectors

Find the equation to the pair of angle bisectors of the pair of lines $(ax+by)^2=3(bx-ay)^2$. Efforts: $$(ax+by)^2=3(bx-ay)^2$$ After simplifying, I got: $$x^2(a^2-3b^2)+8abxy+y^2(b^2-3a^2)=0$$ Now, what should I do next?
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Proving the square formed by pairs of lines

Show that the two pairs of lines $12x^2+7xy-12y^2=0, 12x^2+7xy-12y^2-x+7y-1=0$ form a square. I know that both the equations represent a pair of straight lines. Also the first equation represents a pair of straight lines through origin which are as…
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Finding mid-point of $BC$ if point $A$, orthocenter and circumcenter are given in a triangle

If in a triangle $ABC$, $A \equiv (1,10)$, circumcenter $\equiv (-\frac13, \frac23)$ and orthocenter $\equiv (\frac{11}3, \frac43)$ then the coordinates of mid-point of side opposite to A is? Here clearly point $Q$ is circumcenter and point $P$…
manshu
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Proving equilateral triangle

Show that the lines $x^2+16xy-11y^2=0$ form an equilateral triangle with the line $2x+y+1=0$ and find its area. --------________________________--------- My solution is here; Here $x^2+16xy-11y^2=0$ represents a pair of straight lines. Comparing…
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Calculating the area of Triangle

Find the area of triangle formed by the lines $x^2+4xy+y^2=0$ and $x+y=1$. I know that the equation $x^2+4xy+y^2=0$ represents a pair of straight lines but how do i factorize it to get the two lines represented by it.
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line parallel to x-axis and arbitrary intersection test

I am going through code snippets that calculate the x-intersection point between the line parallel to the x-ais and an arbitrary line between points (x1,y1) and (x2,y2). The code snippet does the following: double t = (x2 - x1)/(y2 - y1); xDbl =…
sajis997
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General equation for a line contained in a plane and passing through a point

I have a vector $n$ and I seek a parametric equation for a line that is orthogonal to $n$ and passes through a point $(a,b,c)$. I got the equation of the plane formed by the normal vector and that contains the point using…
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