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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The area of the quadrilateral whose vertices are $(2,1)$....

The area of the quadrilateral whose vertices are $(2,1)$, $(-1,3)$, $(-3,-1)$ and $(3,-4)$ is My attempt: I guess the area of quadrilateral $$=\dfrac {1}{2} |x_1y_2 - x_2y_1 + x_2y_3 -x_3y_2 +x_3y_4-x_4y_3 +x_4y_1 - x_1y_4|$$. An I right ?
pi-π
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A chord of the ellipse $ \frac{x^2}{25}+\frac{y^2}{16} = 1$ t intersect the ellipse at $A$ and $B$. then maximum of $PA\cdot PB$

Through point $P(2,2)$ is drawn a chord of the ellipse $\frac{x^2}{25}+\frac{y^2}{16} = 1$ such that it intersect the ellipse at $A$ and $B$. then maximum value of $PA\cdot PB$ is Attempt: point $P(2,2)$ lie inside the ellipse…
DXT
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Given 2 points and a line which contains the center point

Find the general equation of the circle containing $(-4,-2)$ and $(2,0)$, and whose center is contained on the line $5x-2y=19$.
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Find both cathetus values given only tan (angle) and hypothenuse

I am developing a game and came to a problem that couldn't solve yet. In a given scenario, an opponent shoots at a target in a 2D environment. At the beginning, all that I got is only the position of the enemy (say, (Ex, Ey)) and of the player (Px,…
Fnr
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Distance from a Point to a Line Problem

In $\triangle ABC : A(-2,7)$ and $C(7,-5)$. The length of the altitude to $AC$ is $5$ and the length of the altitude to $BC$ is $\sqrt45$. I need to find the coordinates of $B$, given that this point is below $AC$. I have started by finding the…
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Changing the gradient of a line by degrees

I know that to find the perpendicular of a linear line of form $y = m x + c$, you create a new equation with a gradient of the negative reciprocal $-1/m$. This is how you change it by 90 degrees. Is there a way of doing this by 30 degrees say? Is…
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Reduce $F(x,y)=0$ to canonical form of parabola

I know, from calculating $\delta$ and $\Delta$, that the following function represents parabola. $$x^2-2xy+y^2-2x+27y+10=0$$ But how can I get it to its canonical form: $y^2=2px$ ? Essentially I need to sketch it, not precisely draw it.
tyr
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How to prove that 3 points are on the same line by the distance between the points

If I am given 3 points, e.g. $A=(-2,-1)$, $B=(1,3)$, $C=(7,11)$ and I wish to prove that they are all on the same line using the distance between all pairs, how do I do that? I know that $AB=5$, $AC=15$ and $BC=10$. According to the triangle…
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Definition diagonal arbitrary quadrilateral

Given A convex quadrilateral whose sides are defined as (a=200, b=140, c=180, d=160). Diagonally (d1, d2) are equal. Task How to determine the length of the diagonal (d1, d2) with up to six decimal places? Numerical results Obtained in Mathcad using…
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Equations of straight line

The line joining the points A(-1,3) and B(5,15) meets the axes at P and Q. Find the equation of AB and calculate the length of PQ. How to calculate the length of PQ??
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Can you determine what area a point is in within a box?

I have a quadrilateral (not an exact rectangle or parallelogram) and can determine whether or not a point is in the box by using solutions found here: How to check if a point is inside a rectangle? I have a series of points and I want to…
paulST
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Prove this relation for the given hyperbola

Given hyperbola: $$\left(\frac{x^2}{a^2-b^2}\right)-\left(\frac{y^2}{a^3-b^3}\right)=1$$ Amswer given is (1). I only got the equality part of the given answer. I don't know how inequality will be formed in my solution. Did I miss something in my…
Arishta
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How to find the equations of the planes from the line as intersection?

The equation of the line as intersection of the two planes is: ${x=1-2t, y=3-t, z=2+8t}$
Kevin
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Rotated Conic Section without $x$ and $y$

I'm looking for a proof of this following theorem : Given $ax^2+bxy+cy^2=k$, to standardize equation of this conic section with coefficient of $x'$ being $a'$ and coefficient of $y'$ being $b'$, then $a'$ and $b'$ are the solutions to this…
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Rotated Conic Section without $xy$ term

I'm looking for a proof of this following theorem : Given $ax^2+bxy+cy^2=k$, to standardize equation of this conic section with coefficient of $x'$ being $a'$ and coefficient of $y'$ being $b'$, then $a'$ and $b'$ are the solutions to this…