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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Find the Locus of the foot of the perpendicular.

Consider the tangent planes to the surface $S: \frac{x^2}{2}+y^2+z^2=1$ that passing through the point $P(1,1,1)$, then draw the perpendicular to the tangent plane from the centre of the surface $S$. What is the Locus of the foot of the…
Bob
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Coordinate geometry with slopes for each side

The problem: A trapezoid $ABCD$ lies on the xy-plane. The slopes of lines $BC$ and $AD$ are both $\frac{1}{3}$, and the slope of line $AB$ is $-\frac{2}{3}$. Given that $AB = CD$ and $BC < AD$, the absolute value of the slope of line $CD$ can be…
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Quadratic equation with parameter

Stuck solving this equation. Full text: For what real values of the parameter do the common solutions of the equation became identical? 1. y = mx - 1 2. x^2 = 4y ans. m = +/- 1 2a. x^2 - 4y = 0 So i started by substituting 1. into 2a. x^2 - 4 *…
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Prove that the point-slope form of a linear equation does not depend on the point

I am stucked on the following challenge: "If the line determined by two distinct points $(x_1, y_1)$ and $(x_2, y_2)$ is not vertical, and therefore has slope $(y_2-y_1)/(x_2-x_1)$, show that the point-slope form of its equation is the same…
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Trouble with textbook problem and questionable proof of midpoint formula.

I need help with problem 33. I don’t really know how to go about solving it. Whenever I try to express the vertices as variables, everything just ends up being really messy. For the guy to proof of the midpoint formula given in problem 35, the…
punk4me
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For given line, find the locus of foot of perpendicular from origin

for a variable line $\frac xa +\frac yb =1$, find the locus of foot of perpendicular drawn from origin to the line under the condition that $\frac{1}{a^2}+\frac{1}{b^2}=\frac{1}{c^2}$ The line perpendicular to this line and passing through origin…
Aditya
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Distance of an observer above the surface of the earth to his Horizon

The earth's diameter $D$ is approx. $12742$ km. a) Under the assumption of an exact spherical shape of the earth, show that the distance $f(h)$ of an observer who is at height $h> 0$ above the surface of the earth to his Horizon is given by $f (h) =…
Mary Star
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does $\frac{d(p_1,p_2)}{d(p_2,p_3)}=\frac{d(q_1,q_2)}{d(q_2,q_3)}$

the problem is : if $p_1,p_2,p_3$ are collinier points in the space , and for an arbitrary line $l$ we have that $q_1,q_2,q_3$ are the image of $p_1,p_2,p_3$ on $l$ respectivly. then does the following hold? …
Mr.C
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How to prove that the intersection of 3 planes is a line?

Consider the planes: $$P1:x - y = 0$$ $$P2:y-z = 0$$ $$P3:-x+z = 0$$ Prove that the intersection of the planes is a line. My solution: Solving the system I've obtained that $x=y=z$ and I made the notation $x=t$. From here we get the parametric…
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Is it possible to draw all regular polygons on a double grid formed by a rational and an irrational grid, superimposed?

Is it possible to draw any regular polygon in such a way that its vertices be on the double grid, made of a rational and an irrational grid, superimposed, like in the image below? If yes, what would be the step of the irrational grid? (It is,…
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Why don't these two normal vectors have a 0 or a 180 degree angle between them when graphed?

There's a plane that is given with the equation $2x-3y+z+2=0$ and there's a line equation $\frac{x+3}{-1}=\frac{y}{3}=\frac{z-1}{P}$. I need to find the missing number $P$, when the line is parallel to the plane. As number $P$ is a coordinate of the…
anon
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Geometric question?

First of all, is it Geometric? Image of the drafted: I need help solving this question, and I am completely lost on how can I solve this. Could anyone explain the way of solving this geometric question? Here is a drafting of the two lines I and…
user73230
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Find basis and dimension in $\mathbb{R}^6$

Given a set $A=(x_1,x_2,x_3,x_4,x_5,x_6)$ in $\mathbb{R}^6$, that follows $$5x_1+x_2+x_3+x_4+x_5+5x_6=0$$ How to find a basis and dimension to its subspace? By now, I only proved that the set is linear dependent, but I have no idea about how to…
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Coordinate of point, given a line segment

It is given that points A = (−2, 1) B = (4, −1) form a segment, and it is asked at which point in y axis (when x = 0) when you "look at" or draw segments to points A and B there is a 90 degree angle. How do you solve this? The answer is 0,3 and…
Jeekim
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How to Find an Equation of a Plane Containing Point Q and Perpendicular to Plane P

Given point $Q(1, 0, -1)$ and plane $P: 2x + 3y - 2z = 6$, how do I find an equation of a plane that contains point $Q$ and is perpendicular to plane $P$?
muw
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