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
1
vote
4 answers

Find the equation of a parabola (in general form)

Find the equation of the parabola with axis parallel to the $y$-axis, passing through $(1/2,-5/2),(3/2,-9/4)$ and $(-7/2,3/2)$.
mona
  • 119
1
vote
1 answer

Intuitive understanding of tangents and graphs

Consider this locus Now a property of this is that the angle between the tangent at any point B and the line joining origin to B is constant . My question is why does this happening? I was able to prove this but don't understand why this…
1
vote
2 answers

Line-function intersection in $3D$ space

So I'm currently programming a shader in hlsl (more specifically, shaderlab, unity's version of hlsl) where I want to simulate rocket engine's plumes. These plumes tend to follow an equation that I simplified quite a lot to be (where $A$ represents…
1
vote
1 answer

hyperbola eccentricity in a concrete example not working out

Let's say we have a hyperbola with the focus at $F=(2, 3)$, directrix of $y=-x$, and eccentricity $e=\sqrt{2}$. If I understand correctly, that should mean that the distance from any point $P$ on the hyperbola to the focus is $\sqrt{2}$ times larger…
S11n
  • 898
1
vote
3 answers

Intersection between the plane $y-x=0$ and $x^2+y^2+z^2=4$

When I plug in $y=x$ to the other equation I get an elipse equation. But when plotting it 3d I see the intersection curve is a circle. What am I supposed to do?
Dor
  • 45
1
vote
1 answer

Cosine law in Cyclic quadrilateral

Let $\square$ ABDC is cyclic quadrilateral , and $\triangle$ ABC is equilateral triangle of length a. Express $ \overline {DA} ^4 + \overline {DB} ^4 + \overline {DC}^4 $ using terms of a. Let $ \overline {DA} =x , \overline {DB} =y , \overline…
Snupi
  • 131
1
vote
1 answer

Calculate the angle between two concurrent lines

My teacher gave me a list with the following exercise: Let $r$ be the line that passes through $P = (1, 0, 5)$ and has directional vector $\vec{u} = (0, 1, -3)$ and $s$ the line that intersects the planes $\pi_{1} = \{(x, y, z); x = 1\}$ and…
1
vote
2 answers

How many points these ellipses intersect.

If $a \neq b$, how many points theses ellipses $\frac{x²}{a²} + \frac{y²}{b²} = 1$, $\frac{x²}{b²} + \frac{y²}{a²} = 1$ intersect themselves. My attempt: I did $y² = b² -\frac{x²}{a²}b² = a² -\frac{x²}{b²}a² $ and I found $x = +- \frac{ab}{\sqrt{a²+…
user1158833
1
vote
0 answers

Minimum distance between parabola and line

Given the parabola $ 9 x^2 - 12 x y + 4 y^2 + 2 x + 8 y - 10 = 0 $ Find its shortest distance to the line $ x - 2 y + 8 = 0 $ My attempt: First, we have to make sure that the line does not intersect the parabola, so substituting the line into the…
Hosam Hajeer
  • 21,978
1
vote
3 answers

Let $A(-2;-2)$ and $B(4;4)$ are vertices of the square $ABCD$

Let $A(-2;-2)$ and $B(4;4)$ are vertices of the square $ABCD$. If the intersection of the diagonals of the square lies in the second quadrant, find its coordinates. I am not sure what exactly we are supposed to use in order to find the center $O$…
1
vote
1 answer

The line $y+2x=11$ is a tangent to a circle with a centre $P(1;-1)$ at the point $Q(x;y)$. Determine the equation of the radius $PQ$

I already find the radius to be $10$ units. I did that by substituting $p$ values aka the centre into the equation of a circle
1
vote
0 answers

Axioms of analytical geometry

The approach in analytic geometry is somewhat different. We define concepts such as point, line, on, between, etc., but we do so in terms of real numbers, which are left undefined. The resulting mathematical structure is called an analytic mode1 of…
Kerem
  • 11
1
vote
1 answer

Find the radical centre of the four spheres :$x^2+y^2+z^2+2x+2y+2z+2=0,x^2+y^2+z^2+4y=0,x^2+y^2+z^2+3x-2y+8z+6=0,x^2+y^2+z^2-x+4y-6z-2=0$

Determine the radical centre of the spheres $x^2+y^2+z^2+2x+2y+2z+2=0,x^2+y^2+z^2+4y=0,x^2+y^2+z^2+3x-2y+8z+6=0,x^2+y^2+z^2-x+4y-6z-2=0.$ I tried solving the problem by assuming…
Arthur
  • 2,614
1
vote
1 answer

What does the $z-z_0=m(y-y_0)$ equation do in this article? and why is it written into the sphere equation?, and how this 2 equations derived?

I'm reading this topic Analytic Treatment of the Perspective View of a Circle in this article. I don't understand the subject, so I decided to analyze it piece by piece. $z-z_0 = m(y-y_0)$ What is the equation used for? And why do they put it…
1
vote
0 answers

What's the true meaning of the definition of cylinder "A cylinder is a surface generated by a variable straight line which moves parallel to a fixed

I was going through a definition about cylinder which states that : A cylinder is a surface generated by a variable straight line which moves parallel to a fixed line and intersects a fixed curve not lying in a plane parallel to the fixed line or…
Arthur
  • 2,614