Indentify the typer of conic section and its vertices&foci. Calc II

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In summary: You correctly identified the conic section as a hyperbola and found the center, vertices, and foci using the standard form equation. Well done!
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Homework Statement



Identify the type of conic section whose equation is given as y^2+2y=4x^2+3
Also find its vertices and foci
(y-k)^2/a^2-(x-h)^2/b^2=1

Homework Equations



I believe when you have x&y ^2 in an equation it can be either an ellipse or a hyperbola but if the signs are opposite it is a hyperbola. vertices ± a from center, foci ± c from center.

The Attempt at a Solution


I begin by rewriting the equation y^2+2y=4x^2+3 as
y^2+2y-4x^2=3 thus allowing me to recognize that the powers or x/y ^2 are opposite, and thus the type of conic section is a hyperbola.
I complete the square for the y(s) of the equation which gives me (y+1)^2-1
and I now rewrite the equation as (y+1)^2-4x^2=3+1, (y+1)^2-4x^2=4
there is no way of completing the square for 4x^2 however since I know the equation is in the form (x-h)^2 I will rewrite -4x^2 as -4(x-0)^2
I will rewrite the equation again as:
(y+1)^2-4(x-0)^2=4 and again in the form of (y-k)^2/a^2-(x-h)^2/b^2=1
as, (y+1)^2/4 - (x-0)^2/1 = 1
thus I have a^2=4, b^2=1, and a=2, b=1
I know have all the necessary things to solve for the question.
Center = (h,k)= (0,-1)
vertices are ± a from center on axis, a =2
thus vertices are (0,-1 ± 2 )
foci are ± c from center, c^2=a^2+b^2= 1+4= √5
foci: (0, -1±√5)

That is all my work/solutions for this problem.
Any help with what I may have done wrong and how to learn how to correct is, or even just saying "correct" is appreciated thank you.
 
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  • #2
StudentofSci said:

Homework Statement



Identify the type of conic section whose equation is given as y^2+2y=4x^2+3
Also find its vertices and foci
(y-k)^2/a^2-(x-h)^2/b^2=1

Homework Equations



I believe when you have x&y ^2 in an equation it can be either an ellipse or a hyperbola but if the signs are opposite it is a hyperbola. vertices ± a from center, foci ± c from center.

The Attempt at a Solution


I begin by rewriting the equation y^2+2y=4x^2+3 as
y^2+2y-4x^2=3 thus allowing me to recognize that the powers or x/y ^2 are opposite, and thus the type of conic section is a hyperbola.
I complete the square for the y(s) of the equation which gives me (y+1)^2-1
and I now rewrite the equation as (y+1)^2-4x^2=3+1, (y+1)^2-4x^2=4
there is no way of completing the square for 4x^2 however since I know the equation is in the form (x-h)^2 I will rewrite -4x^2 as -4(x-0)^2
Yes, that is "completing the square" for [itex]x^2[/itex].

I will rewrite the equation again as:
(y+1)^2-4(x-0)^2=4 and again in the form of (y-k)^2/a^2-(x-h)^2/b^2=1
as, (y+1)^2/4 - (x-0)^2/1 = 1
thus I have a^2=4, b^2=1, and a=2, b=1
I know have all the necessary things to solve for the question.
Center = (h,k)= (0,-1)
vertices are ± a from center on axis, a =2
thus vertices are (0,-1 ± 2 )
foci are ± c from center, c^2=a^2+b^2= 1+4= √5
foci: (0, -1±√5)

That is all my work/solutions for this problem.
Any help with what I may have done wrong and how to learn how to correct is, or even just saying "correct" is appreciated thank you.
It all looks correct to me.
 

1. What is a conic section?

A conic section is a curve that is formed by the intersection of a plane and a double cone. It can take the shape of a circle, ellipse, parabola, or hyperbola.

2. How do you identify the type of conic section?

The type of conic section can be determined by the equation of the curve. A circle has an equation in the form (x-h)^2 + (y-k)^2 = r^2, an ellipse has an equation in the form (x-h)^2/a^2 + (y-k)^2/b^2 = 1, a parabola has an equation in the form y = ax^2 + bx + c, and a hyperbola has an equation in the form (x-h)^2/a^2 - (y-k)^2/b^2 = 1.

3. What are the vertices of a conic section?

The vertices of a conic section are the points where the curve intersects the major axis. For a circle, ellipse, and hyperbola, there are two vertices, while for a parabola, there is only one vertex.

4. How do you find the foci of a conic section?

The foci of a conic section can be found by using the equation c^2 = a^2 + b^2, where c is the distance from the center to the focus, and a and b are the lengths of the semi-major and semi-minor axes, respectively. For a circle, the foci are located at the center of the circle. For an ellipse, the foci are located on the major axis, and for a hyperbola, the foci are located on the transverse axis.

5. Why is it important to identify the type of conic section and its vertices and foci?

Identifying the type of conic section and its vertices and foci can help in graphing the curve, solving real-world problems, and understanding the properties of the curve. It also allows for the use of specific formulas and techniques for solving problems involving conic sections.

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