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
3
votes
5 answers

How exactly one can show parametric equations in a graph

I'm trying to understand parametric equations, it looks simple but it tricks me. $x = 3-2t\\y=1+t\\z=2+3t$ How do I plot it ? I mean, where's $t$ in the graph?
user2860452
  • 153
  • 1
  • 2
  • 10
3
votes
2 answers

Find the condition that the diagonals of a parallelogram formed by $ax+by+c=0$.

Find the condition that the.diagonals of a parallelogram formed by $ax+by+c=0$, $ax+by+c'=0$, $a'x+b'y+c=0$ and $a'x+b'y+c'=0$ are at right angles. My Attempt: The equation of diagonal passing through the point of intersection of $ax+by+c=0$ and…
pi-π
  • 7,416
3
votes
2 answers

What is shortest path between two points $P (0,0)$ and $Q (12,16)$ such that the path doesn't cross the circle $(x-6)^2 +(y-8)^2 = 25$?

What is shortest path between two points $P (0,0)$ and $Q (12,16)$ such that the path doesn't cross the circle $(x-6)^2 +(y-8)^2 = 25$ ? Edit Here is a graph of path of length $10+5\pi$ and this value is one of the options in the problem The…
user373141
  • 2,503
3
votes
1 answer

Suppose $A$, $B$ $C$ are three non collinear points (A challenging problem)

Please help me. I didn't get any idea to solve this challenging problem: Suppose $A, B, C$ are three non-collinear points corresponding to complex numbers $$z_0 = ai, \;z_1 = \frac{1}{2}+bi,\; z_2 = 1+ci$$ ($a, b$ and $c$ being real numbers),…
Aryabhatta
  • 645
  • 1
  • 11
  • 23
3
votes
1 answer

Square with sides curving inwards

Whilst plotting some charts on Desmos, it was noticed that the following formula $$x^{m}+y^{m}=k\\ \text{where}\begin{cases} 00\end{cases}$$ plots a square with sides curving inwards. Questions: 1. Why is…
3
votes
1 answer

Offsetting a curve in 2D

I'd like to "move" a curve $d$ (offset) units "up" (actually in the sense that the perpendicular distance between the curves is always constant). The objective is to create a channel that has constant width. I want the shape of the second curve such…
Clash
  • 1,401
3
votes
2 answers

length of the shortest path connecting a point and another point on circle.

The length of the shortest path that begins at $(2,5)$ touches the x-axis and then end at point on the circle $x^2+y^2+12x-20y+120=0$ $\bf{My\; Try::}$ Equation of circle in standard form :: $(x+6)^2+(y-10)^2=4^2$ So any point on the circle is…
juantheron
  • 53,015
3
votes
4 answers

Can we find incentre of a triangle by using equation of lines?

My question is, in the manner which we find the orthocentre of a triangle merely by using it's side's line equations, can we also find the incentre? For example, consider, $$3x+4y-7=0$$ $$4x-3y+19=0$$ $$18x-6y+7=0$$ We can find the orthocentre of…
3
votes
2 answers

Projection of a point on a line

Find the projection of the point $(-6,4)$ onto the line $4x-5y+3=0$ I can find the distance between the point and the line, but I do not think it can help
gbox
  • 12,867
3
votes
1 answer

A question about classifying conics, from Garrity's book

For a general conic $$ ax^2 + bxy + cy^2 + dx + ey + h = 0$$ we see that, when rearranged and thought of as a quadratic in $x$, the discriminant of the resulting quadratic is $$\Delta_x(y) = (b^2 - 4ac)y^2 + (2bd - 4ae)y + (d^2 - 4ah) = \delta y^2 +…
3
votes
3 answers

Prove that points A, B, K and L lie on a circle $c$

In an acute-angled triangle ABC with height CD, K and L are orthogonal projections through D respectively on AC and BC. Prove that points A, B, K and L lie on a circle $c$. I tried to prove that triangles ADK and DLB are of the same form, but…
user270346
3
votes
2 answers

Find the equation of the straight line which is both a tangent and normal to the curve $x=3t^2,y=2t^3?$

Find the equation of the straight line which is both a tangent and normal to the curve $x=3t^2,y=2t^3?$ I found $\frac{dy}{dx}=t$.Let the curve has tangent at point $P(t_1)i.e.(3t_1^2,2t_1^3)$ and let the curve has same line as normal at point…
Vinod Kumar Punia
  • 5,648
  • 2
  • 41
  • 96
3
votes
2 answers

Finding Points That Lie On A 3D Line?

Which of the points $P(1, 2, 0), Q(−5, 1, 5), R(−4, 2, 5)$ lie on the line $l : r(t) = (i + 2j) + t(6i + j − 5k)?$ $l3 : r3(ν) = (6i − j) − ν(2i − 4j + 6k),$ $l4 : r4(w) = (1/2+ 1/2w)i − wj − (1 + 2/3w)k.$ What I have tried so far is to plug in…
Jon
  • 1,920
3
votes
0 answers

Eccentricity of $9x^2 + 4y^2 - 24y + 144 = 0$

For a National Board Exam Review: Compute the eccentricity of a given curve $9x^2 + 4y^2 - 24y + 144 = 0$ Answer is $0.75$ I try: $$9x^2 + 4y^2 - 24y + 144 = 0$$ $$9x^2 + 4(y^2 - 6y + 9) = -144 + 36$$ $$9x^2 + 4(y-3)^2 =…
james
  • 1,017
3
votes
2 answers

Finding the other end of the Diameter

For a National Board Exam Review A circle has it center at $(3,-2)$ and one end of a diameter at $(7,2)$. Find the other end of the diameter. Answer is $(-1,6)$ $$m=\frac{y^2-y^1}{x^2-x^1}=\frac{2-(-2) }{7-3}$$ $$=(3-7)^2+(-2-2)^2=r^2=32$$ $$r…
james
  • 1,017