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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condition for pair of straight line equation

While determining the condition for the pair of straight line equation $$ax^2+2hxy+by^2+2gx+2fy+c=0$$ i.e …
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Equation of chord subtending an angle at the vertex

I need to find the equations of the chords of the parabola subtending an angle of $45°$ at the vertex of $y²=4ax$ and passing through $(-6a,0)$. How do I approach this? I don't know the slope of the lines, thus can't find the equations of the…
Techie5879
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Plane cut the cone in perpendicular generators

Question :- Prove that if a plane cut the cone $$ax^2+by^2+cz^2=0$$ in perpendicular generators, it touches the cone $$\frac{x^2}{b+c}+\frac{y^2}{a+c}+\frac{z^2}{a+b}=0$$ In solution :- Consider a plane $$ux+vy+wz=0$$ Now , consider a section of…
messi
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Plane cut the cone perpendicularly

I came across a problem which requires to prove that plane ax+by+cz=0 cuts cone xy+yz+xz=0 in perpendicular lines if 1/a+1/b+1/c=0 Solution to the problem says that since given cone is generated by three mutually perpendicular planes, hence plane…
messi
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If a diameter has endpoints (a,b) and (c,d), prove that the equation of the circle can be written $(x-a)(x-c)+(y-b)(y-d)=0$

I am faced with the question in the title and have shown it on my own, but my friend has been asking how to solve it and I want to see if there is a quicker method than what I have used. I stopped because I originally expanded out all of the…
Jamminermit
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How to find the equation of a pair of straight lines using the joint equation?

Could you please explain, how to find the equations of two straight lines using the joint equation - $ax^2+2hxy+by^2+2gx+2fy+c=0$. To convert the given pair of straight lines into the joint equation, I would just multiply the two equations as given…
Vishnu
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Equation of a circle tangent to the $y$ axis

The problem is: Find the general equation of a circumference with center at $(-4,3)$ and tanget to the $y$ axis I know that calculating the distance between the center and any point on the circumference gives me the radios. And then the general…
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Find minimum bounding rectangle of an arc

How do you find the minimum bounding rectangle of a circular arc ? You are given the starting point, ending point and another point on the arc. With these points, I've found out the co-ordinates for the centre of the circle and the radius. I'm…
rohit89
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Joint equation of pair of lines joining the origin and the points of intersection of a line and curve

My teacher told me that if I am given a line $L_1$ and a curve $C_1$ $$L_1 : lx + my + n=0 $$ $$C_1 : ax^2 + 2hxy + by^2 + 2gx + 2fy + c = 0$$ If $n \not= 0$ and if the line $L_1$ cuts the curve $C_1$ at $2$ points, then the joint equation of…
eem
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Intersection points of a Triangle and a Circle

How can I find all intersection points of the following circle and triangle? Triangle $$A:=\begin{pmatrix}22\\-1.5\\1 \end{pmatrix} B:=\begin{pmatrix}27\\-2.25\\4 \end{pmatrix} C:=\begin{pmatrix}25.2\\-2\\4.7…
libjup
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Calculating volume using double integral

I am trying to find the volume above $\ z = 0 $ under $\ z = x^2 + y^2 $ and inside the cylinder $\ x^2+y^2 = 2x $ using double integral. the intersection between the cylnder and the paraboloid is the plane $\ z = 2x $ and the project on $\ xy $…
bm1125
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Find tangents to a circle parallel to the straight line

Find tangents to a circle $x^2+y^2=5$ parallel to the straight line $2x-y+1=0$ My solution: $$x^2+y^2=5$$ $$S=(0,0)$$ $$r=\sqrt{5}$$ $$y=2x-1$$ $$a=2$$ Searching for b $$y=2x+b$$ Using following…
Pakuss
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Find the equation of tangent and normal for $y=f(x)$, if, $ y=x^{2}-2x+3$ and tangent is perpendicular to line $x+y-1=0$

I am supposed to find the equation of tangent and normal for $y=f(x)$, if, $ y=x^{2}-2x+3$ and tangent is perpendicular to line $x+y-1=0$. My solution for tangent is $y-x-3/4=0$ and for normal is $y+x-15/4=0$. Is it correct? Thanks!
J. Doe
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How to calcultate perimeter of region R such that it contains the given points?

Consider $6$ points located at $P_0=(0,0), P_1=(0,4), P_2=(4,0), P_3=(-2,-2), P_4=(3,3), P_5=(5,5)$. Let $R$ be the region consisting of all points in the plane whose distance from $P_0$ is smaller than that from any other $P_i$, $i=1,2,3,4,5$. Find…
Raghav
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Ellipse bounding rectangle and quadrangle bounding ellipse

I am stuck solving this geometry problem. Given ellipse $x^2 + 4 y^2 = 32$ is bounding a rectangle whose height is the double of its width. At the apexes of rectangle are tangent lines to the ellipse. What is the ratio of rectangle area and …