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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How to prove $\frac{y^2-x^2}{x+y+1}=\pm1$ is a hyperbola?

How to prove $\frac{y^2-x^2}{x+y+1}=\pm1$ is a hyperbola, knowing the canonical form is $\frac{y^2}{a^2}-\frac{x^2}{b^2}=\pm1$ where $a$ and $b$ are constants? Thanks !
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Triangle - coordinate geometry problem

Let ABC be a triangle. Let BE and CF be internal angle bisectors of B and C respectively with E on AC and F on AB. Suppose X is a point on the segment CF such that AX is perpendicular to CF; and Y is a point on the segment BE such that AY…
user2369284
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Coordinate Geometry Oblique Coordinates Problem

This is a elementary geometry problem which I have tried to solve using coordinate geometry but it is resulting in an impossible and impractical result. Maybe I have some misconceptions with oblique coordinates. So please help me with my…
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Distance between skew lines - correct method ?

If we have two skew lines in $\mathbb R^3$, $\vec r_{1} = \vec a + \lambda\vec d_1$ and $\vec r_{2} = \vec b + \mu\vec d_2$ then at their closest point, the difference vector $\vec r_2 - \vec r_1$ is perpendicular to both $\vec r_1$ and $\vec r_2$,…
ukmaths
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How to do this problem with vectors?

A plane flies in a direction NW at an airspeed of $141$ km/hr. If the wind at the plane's cruise altitude is blowing with a speed of $100$ km/hr directly from the north, what is the plane's actual speed and direction relative to the ground? So I'm…
Phaptitude
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Tangents from a certain point, to a circle?

We have a circle with radius 2, centred on the origin. Find the equation of the lines passing through the point $(0,4)$ which are tangent to the circle. So we have the circle $$x^2 + y^2 = 4$$ We need 2 lines $$y=ax+4$$ So if you fill that in the…
Phaptitude
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find equation of a plane P containing 2 points and parallel to a cross vector

Given: A(0,3,1), B(1,1,4), A'(0,1,0), B'(1,-3,3). Find the equation of plane (P) containing A and B and parallel to the vector AB x A'B'. Find the equation of plane (Q) containing A' and B' and parallel to the vector AB x A'B'.
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Altitudes of a hyperbola

I was doing my engineering graphics assignment and I came across this question A cone of base 60mm diameter and slant height 75mm rests with its base on the horizontal plane. It is cut by an auxiliarry inclined plane such that the true shape of the…
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Equation of a circle given two points and tangent line

I am given that $P(-3,-1)$ and $Q(5,3)$ are points of the circle. Also, the line $L:0=x+2y-13$ is tangent to said circle. The objective is to find the equation of the circle. I thought of a way for solving this, but it doesn't seem to be the best…
OFRBG
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Determining vector line equation from two planes.

Determine a vector equation of the line of intersection of the planes p1: $3x - y + 4z - 2 = 0$ and p2: $x + 6y + 10z + 8 = 0$. I know that I can find the cross product of the normals of these vectors (direction vector), but for a line, i need a…
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Analytic Geometry: Point coordinates, same distance from two points

Given are two points, $P1(x_1, y_2)$ and $P2(x_2, y_2)$, and distance $a$. Now I want to find the two points $T1$ and $T2$. $$d(P1,T1) = d(P2, T1) = a = d(P1,T2) = d(P2, T2)$$ Eg: (T1 and T2 are my two points I want to find) T1 …
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Linear separability in a 2×2×2 cube

Essentially, linearly separable points are just those corners that can be cut off with just one slice as marked out by a hyperplane. Can someone please explain how many cases there are for a $2\times2\times2$ cube? The number of linearly separable…
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Proof that all congruent shapes that have the same orientation are the result of a rigid motion

It seems pretty intuitive, and I have seen many sources make this claim. From what I've seen, congruence in geometry is defined as a direct isometry between two shapes, that is, an isometry that preservers handedness. Here is what Wikipedia…
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Cartesian equation of an epicycloid

So I've been working on a game for three months -some kind of air hockey- and players play in fields with various shapes in a two-dimensional plane. Recently, I wanted to make one of these fields looking like an epicycloid, the one with four…
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Tangents to $y=ax^2+bx+c$ from roots

Let $y=ax^2+bx+c$ be a parabola and roots of parabola be $x_1,x_2$. Show that If the tangents drawn from the points where the parabola intersects the $x$-axis are perpendicular to each other, the discriminant of the parabola equation is $1$. My…