<< Chapter < Page Chapter >> Page >

Identify the conic for each of the following without rotating axes.

  1. x 2 9 x y + 3 y 2 12 = 0
  2. 10 x 2 9 x y + 4 y 2 4 = 0
  1. hyperbola
  2. ellipse
Got questions? Get instant answers now!

Access this online resource for additional instruction and practice with conic sections and rotation of axes.

Key equations

General Form equation of a conic section A x 2 + B x y + C y 2 + D x + E y + F = 0
Rotation of a conic section x = x cos   θ y sin   θ y = x sin   θ + y cos   θ
Angle of rotation θ , where  cot ( 2 θ ) = A C B

Key concepts

  • Four basic shapes can result from the intersection of a plane with a pair of right circular cones connected tail to tail. They include an ellipse, a circle, a hyperbola, and a parabola.
  • A nondegenerate conic section has the general form A x 2 + B x y + C y 2 + D x + E y + F = 0 where A , B and C are not all zero. The values of A , B , and C determine the type of conic. See [link] .
  • Equations of conic sections with an x y term have been rotated about the origin. See [link] .
  • The general form can be transformed into an equation in the x and y coordinate system without the x y term. See [link] and [link] .
  • An expression is described as invariant if it remains unchanged after rotating. Because the discriminant is invariant, observing it enables us to identify the conic section. See [link] .

Section exercises

Verbal

What effect does the x y term have on the graph of a conic section?

The x y term causes a rotation of the graph to occur.

Got questions? Get instant answers now!

If the equation of a conic section is written in the form A x 2 + B y 2 + C x + D y + E = 0 and A B = 0 , what can we conclude?

Got questions? Get instant answers now!

If the equation of a conic section is written in the form A x 2 + B x y + C y 2 + D x + E y + F = 0 , and B 2 4 A C > 0 , what can we conclude?

The conic section is a hyperbola.

Got questions? Get instant answers now!

Given the equation a x 2 + 4 x + 3 y 2 12 = 0 , what can we conclude if a > 0 ?

Got questions? Get instant answers now!

For the equation A x 2 + B x y + C y 2 + D x + E y + F = 0 , the value of θ that satisfies cot ( 2 θ ) = A C B gives us what information?

It gives the angle of rotation of the axes in order to eliminate the x y term.

Got questions? Get instant answers now!

Algebraic

For the following exercises, determine which conic section is represented based on the given equation.

9 x 2 + 4 y 2 + 72 x + 36 y 500 = 0

Got questions? Get instant answers now!

x 2 10 x + 4 y 10 = 0

A B = 0 , parabola

Got questions? Get instant answers now!

2 x 2 2 y 2 + 4 x 6 y 2 = 0

Got questions? Get instant answers now!

4 x 2 y 2 + 8 x 1 = 0

A B = 4 < 0 , hyperbola

Got questions? Get instant answers now!

4 y 2 5 x + 9 y + 1 = 0

Got questions? Get instant answers now!

2 x 2 + 3 y 2 8 x 12 y + 2 = 0

A B = 6 > 0 , ellipse

Got questions? Get instant answers now!

4 x 2 + 9 x y + 4 y 2 36 y 125 = 0

Got questions? Get instant answers now!

3 x 2 + 6 x y + 3 y 2 36 y 125 = 0

B 2 4 A C = 0 , parabola

Got questions? Get instant answers now!

3 x 2 + 3 3 x y 4 y 2 + 9 = 0

Got questions? Get instant answers now!

2 x 2 + 4 3 x y + 6 y 2 6 x 3 = 0

B 2 4 A C = 0 , parabola

Got questions? Get instant answers now!

x 2 + 4 2 x y + 2 y 2 2 y + 1 = 0

Got questions? Get instant answers now!

8 x 2 + 4 2 x y + 4 y 2 10 x + 1 = 0

B 2 4 A C = 96 < 0 , ellipse

Got questions? Get instant answers now!

For the following exercises, find a new representation of the given equation after rotating through the given angle.

3 x 2 + x y + 3 y 2 5 = 0 , θ = 45°

Got questions? Get instant answers now!

4 x 2 x y + 4 y 2 2 = 0 , θ = 45°

7 x 2 + 9 y 2 4 = 0

Got questions? Get instant answers now!

2 x 2 + 8 x y 1 = 0 , θ = 30°

Got questions? Get instant answers now!

2 x 2 + 8 x y + 1 = 0 , θ = 45°

3 x 2 + 2 x y 5 y 2 + 1 = 0

Got questions? Get instant answers now!

4 x 2 + 2 x y + 4 y 2 + y + 2 = 0 , θ = 45°

Got questions? Get instant answers now!

For the following exercises, determine the angle θ that will eliminate the x y term and write the corresponding equation without the x y term.

x 2 + 3 3 x y + 4 y 2 + y 2 = 0

θ = 60 , 11 x 2 y 2 + 3 x + y 4 = 0

Got questions? Get instant answers now!

4 x 2 + 2 3 x y + 6 y 2 + y 2 = 0

Got questions? Get instant answers now!

9 x 2 3 3 x y + 6 y 2 + 4 y 3 = 0

θ = 150 , 21 x 2 + 9 y 2 + 4 x 4 3 y 6 = 0

Got questions? Get instant answers now!

−3 x 2 3 x y 2 y 2 x = 0

Got questions? Get instant answers now!

16 x 2 + 24 x y + 9 y 2 + 6 x 6 y + 2 = 0

θ 36.9 , 125 x 2 + 6 x 42 y + 10 = 0

Got questions? Get instant answers now!

x 2 + 4 x y + 4 y 2 + 3 x 2 = 0

Got questions? Get instant answers now!

x 2 + 4 x y + y 2 2 x + 1 = 0

θ = 45 , 3 x 2 y 2 2 x + 2 y + 1 = 0

Got questions? Get instant answers now!

4 x 2 2 3 x y + 6 y 2 1 = 0

Got questions? Get instant answers now!

Graphical

For the following exercises, rotate through the given angle based on the given equation. Give the new equation and graph the original and rotated equation.

y = x 2 , θ = 45

2 2 ( x + y ) = 1 2 ( x y ) 2

Got questions? Get instant answers now!

x 2 4 + y 2 1 = 1 , θ = 45

( x y ) 2 8 + ( x + y ) 2 2 = 1

Got questions? Get instant answers now!

y 2 16 + x 2 9 = 1 , θ = 45

Got questions? Get instant answers now!

y 2 x 2 = 1 , θ = 45

( x + y ) 2 2 ( x y ) 2 2 = 1

Got questions? Get instant answers now!

x = ( y 1 ) 2 , θ = 30

3 2 x 1 2 y = ( 1 2 x + 3 2 y 1 ) 2

Got questions? Get instant answers now!

x 2 9 + y 2 4 = 1 , θ = 30

Got questions? Get instant answers now!

For the following exercises, graph the equation relative to the x y system in which the equation has no x y term.

x 2 + 10 x y + y 2 6 = 0

Got questions? Get instant answers now!

x 2 10 x y + y 2 24 = 0

Got questions? Get instant answers now!

4 x 2 3 3 x y + y 2 22 = 0

Got questions? Get instant answers now!

6 x 2 + 2 3 x y + 4 y 2 21 = 0

Got questions? Get instant answers now!

11 x 2 + 10 3 x y + y 2 64 = 0

Got questions? Get instant answers now!

21 x 2 + 2 3 x y + 19 y 2 18 = 0

Got questions? Get instant answers now!

16 x 2 + 24 x y + 9 y 2 130 x + 90 y = 0

Got questions? Get instant answers now!

16 x 2 + 24 x y + 9 y 2 60 x + 80 y = 0

Got questions? Get instant answers now!

13 x 2 6 3 x y + 7 y 2 16 = 0

Got questions? Get instant answers now!

4 x 2 4 x y + y 2 8 5 x 16 5 y = 0

Got questions? Get instant answers now!

For the following exercises, determine the angle of rotation in order to eliminate the x y term. Then graph the new set of axes.

6 x 2 5 3 x y + y 2 + 10 x 12 y = 0

Got questions? Get instant answers now!

6 x 2 5 x y + 6 y 2 + 20 x y = 0

θ = 45

Got questions? Get instant answers now!

6 x 2 8 3 x y + 14 y 2 + 10 x 3 y = 0

Got questions? Get instant answers now!

4 x 2 + 6 3 x y + 10 y 2 + 20 x 40 y = 0

θ = 60

Got questions? Get instant answers now!

8 x 2 + 3 x y + 4 y 2 + 2 x 4 = 0

Got questions? Get instant answers now!

16 x 2 + 24 x y + 9 y 2 + 20 x 44 y = 0

θ 36.9

Got questions? Get instant answers now!

For the following exercises, determine the value of k based on the given equation.

Given 4 x 2 + k x y + 16 y 2 + 8 x + 24 y 48 = 0 , find k for the graph to be a parabola.

Got questions? Get instant answers now!

Given 2 x 2 + k x y + 12 y 2 + 10 x 16 y + 28 = 0 , find k for the graph to be an ellipse.

4 6 < k < 4 6

Got questions? Get instant answers now!

Given 3 x 2 + k x y + 4 y 2 6 x + 20 y + 128 = 0 , find k for the graph to be a hyperbola.

Got questions? Get instant answers now!

Given k x 2 + 8 x y + 8 y 2 12 x + 16 y + 18 = 0 , find k for the graph to be a parabola.

k = 2

Got questions? Get instant answers now!

Given 6 x 2 + 12 x y + k y 2 + 16 x + 10 y + 4 = 0 , find k for the graph to be an ellipse.

Got questions? Get instant answers now!

Questions & Answers

what does mean opportunity cost?
Aster Reply
what is poetive effect of population growth
Solomon Reply
what is inflation
Nasir Reply
what is demand
Eleni
what is economics
IMLAN Reply
economics theory describes individual behavior as the result of a process of optimization under constraints the objective to be reached being determined by
Kalkidan
Economics is a branch of social science that deal with How to wise use of resource ,s
Kassie
need
WARKISA
Economic Needs: In economics, needs are goods or services that are necessary for maintaining a certain standard of living. This includes things like healthcare, education, and transportation.
Kalkidan
What is demand and supply
EMPEROR Reply
deman means?
Alex
what is supply?
Alex
ex play supply?
Alex
Money market is a branch or segment of financial market where short-term debt instruments are traded upon. The instruments in this market includes Treasury bills, Bonds, Commercial Papers, Call money among other.
murana Reply
good
Kayode
what is money market
umar Reply
Examine the distinction between theory of comparative cost Advantage and theory of factor proportion
Fatima Reply
What is inflation
Bright Reply
a general and ongoing rise in the level of prices in an economy
AI-Robot
What are the factors that affect demand for a commodity
Florence Reply
price
Kenu
differentiate between demand and supply giving examples
Lambiv Reply
differentiated between demand and supply using examples
Lambiv
what is labour ?
Lambiv
how will I do?
Venny Reply
how is the graph works?I don't fully understand
Rezat Reply
information
Eliyee
devaluation
Eliyee
t
WARKISA
hi guys good evening to all
Lambiv
multiple choice question
Aster Reply
appreciation
Eliyee
explain perfect market
Lindiwe Reply
In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
Ezea
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply
Practice Key Terms 3

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Algebra and trigonometry. OpenStax CNX. Nov 14, 2016 Download for free at https://legacy.cnx.org/content/col11758/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Algebra and trigonometry' conversation and receive update notifications?

Ask