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 all $k$ when lines cross each other inside quadrant 1

\begin{align} kx+5y &= -13\\ x+ky &= 1 \end{align} Find all $k$ when these lines cross each other inside quadrant 1. I used Cramer's rule. I got $x = \dfrac{-13k-5}{k^2-5}$ and $y = \dfrac{k+13}{k^2-5}$. After that I got stuck.
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Coordinate of point $C$ on the line So that Perimeter of a $\triangle ABC$ is minimum

Given $2$ points $A(-2,0)$ and $B(0,4)$ and a line $y=x.$ Find the coordinate of a point $C$ on the line So that Perimeter of a $\triangle ABC$ is minimum $\bf{My\; Try::}$ Let Coordinate of Point $P(x,y)$ Here We have to Minimize $AB+BC+CA =…
juantheron
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Write the equation of a line as the intersection of two planes

The parametric equations are $$x = 2 + 3t$$ $$y = 3-t$$ $$z= 1+t$$ Let $\alpha: A_1x + B_1y + C_1z + D_1 = 0$ and $\beta: A_2x + B_2y + C_2z + D_2 = 0$ be the equations of two intersecting planes. To make it clear, I'm asked to go from to $(x,y,z)…
asd
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Finding the equation of the sphere

Find the equation of the sphere which touches the three coordinate planes and the plane 2x+y+2z=6. Please help me to solve this problem. What does three coordinate planes mean?
Chic
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angle between lines

The angle between two lines is given by $ \tan(\theta) = \big|\frac{m_2-m_1}{1+m_1m_2}\big| $ where $m_1$ and $m_2$ are the slopes of the two lines in question. What is confusing me is the reverse problem. When we try to find the slope of…
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Slopes of lines making an angle to a given line

How does one go about finding the slopes of the lines making a given angle with a line of a given slope ? Say, we have a line of slope m and are said to find the slopes of lines making angle of $\theta$ with said line. How does one find the…
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intersection point between circle and line

The line $-bx + ay + 2b = 0$ intersects circle on points A and B. Circle equation is $$(x-1)^2 + \big(y-\frac{a^2 + b^2 - a}{b}\big)^2 = \frac{(a^2 + b^2 - a)^2 + b^2}{b}$$ or after algebraic-transformations: $$bx^2 + by^2 - 2bx - 2(a^2 + b^2 -…
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Doubt on whether my solution is correct

The question was to prove that the equation $y^3-x^3+3xy(y-x)=0$ represents three lines equally inclined to one another.What i did was i factored out $(y-x)$ and the equation became $$(y-x)(y^2+4xy+x^2)$$. Now, since the other part is a homogeneous…
Ayan Shah
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Analytic Geometry Question

There is a point $M (2,1$) on a Cartesian coordinate system. There is also a point $P (x,y)$. What is the distance $MP$ in $x$ and $y$? I can figure out that $ PM^2$ = $(x-2)^2 + (y-1)^2$, at least, I think so, but how to solve $PM$? I am not the…
JohnPhteven
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Partitioning the unit disc with a parabola to satisfy ratio of areas

Suppose a parabola defined by $y=\lambda x^2$ in the $xy$-plane partitions the unit disk (centered at the origin) into two parts. Which $\lambda>1$, if any, satisfy that the area of the lower part is exactly $\lambda$ times larger than the area of…
Corellian
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For the variable traingle ABC with...

For the variable triangle $ABC$ with fixed vertex at $C(1,2)$ and $A,B$ having co-ordinates $(cos t, sin t), (sin t, -cos t)$ respectively, what is the locus of its centroid? My Approach: The coordinate of centroid $O(x ,y )$ in triangle having…
pi-π
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Find the equations of the tangents from..

Find the equations of the tangents from the point $(0,1)$ to the circle $x^2+y^2-2x-6y+6=0$. My Attempt: Here, $$x^2+y^2-2x-6y+6=0$$ Comparing with $$x^2+y^2+2gx+2fy+c=0$$ Centre $(-g,-f)=(1,3)$ radius $r=\sqrt {g^2+f^2-c}=2units$. Please help me to…
pi-π
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If $ax^2+2hxy+by^2=0$ be the two sides of a $||$gm ..

If $ax^2+2hxy+by^2=0$ be the two sides of a parallelogram and $px+qy=1$ is its one diagonal, prove that the other diagonal is $y(bp-hq)=x(aq-hp)$. My Approach. Here, $ax^2+2hxy+by^2=0$ represents aa pair of lines passing through the origin.…
pi-π
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$P$ and $Q$ are two points on the line...

$P$ and $Q$ are the two points on the line $x-y+1=0$ such that each of them is $5$ units from the origin. Find the co ordinates of two points. My Attempt; Let $P(a,b)$ and $Q(a,b)$ be the co ordinates of two points. Then $$x-y+1=0$$ We can…
pi-π
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Prove that the equation of two planes inclined at an angle $\alpha$ to x-y plane

Prove that the equation of two planes inclined at an angle $\alpha$ to x-y plane and containing the line $y=0, z \cos\beta=x\sin\beta$ is $~~(x^2+y^2) \tan^2\beta+z^2-2zx~\tan\beta=y^2\tan^2\alpha$. My approach: Let $l_1 x+m_1y+n_1z=d_1$ and $l_2…
A. Khan
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