Which conic section is represented by the equation shown below?

[tex]2x^2-9x+4y^2+8x=16[/tex]

A. Parabola
B. Ellipse
C. Circle
D. Hyperbola

Respuesta :

Answer: Option B.  Ellipse

[tex]\frac{(x-\frac{1}{4})^2}{\frac{129}{16}}+\frac{(y-0)^2}{\frac{129}{32}}=1[/tex]

Step-by-step explanation:

To know what type of conic section the function is

[tex]2x ^ 2-9x + 4y ^ 2 + 8x = 16[/tex] we must simplify it.

[tex]2x ^ 2-9x + 4y ^ 2 + 8x = 16\\\\2x^2 -x +4y^2 =16[/tex]

complete the square of the expression:

[tex]2x ^ 2 -x\\\\\\2(x^2 -\frac{1}{2}x)\\\\2(x^2-\frac{1}{2}x +\frac{1}{16})-2\frac{1}{16}\\\\2(x-\frac{1}{4})^2 -\frac{1}{8}[/tex]

So we have

[tex]2(x-\frac{1}{4})^2 -\frac{1}{8}+4y^2 =16\\\\2(x-\frac{1}{4})^2+4y^2 =\frac{129}{8}\\\\\frac{8}{129}[2(x-\frac{1}{4})^2] +\frac{8}{129}[4y^2] =1\\\\\frac{16(x-\frac{1}{4})^2}{129}+\frac{32(y-0)^2}{129}=1[/tex]

[tex]\frac{(x-\frac{1}{4})^2}{\frac{129}{16}}+\frac{(y-0)^2}{\frac{129}{32}}=1[/tex]

We know that the general equation of an ellipse has the form

[tex]\frac{(x-h)^2}{a^2} +\frac{(y-k)^2}{b^2}=1[/tex]

Then the equation

[tex]\frac{(x-\frac{1}{4})^2}{\frac{129}{16}}+\frac{(y-0)^2}{\frac{129}{32}}=1[/tex]

is an ellipse with center [tex](\frac{1}{4}, 0)[/tex]

[tex]a =\sqrt{\frac{129}{16}}[/tex]  and  [tex]b=\sqrt{\frac{129}{32}}[/tex]

Observe the attached image

Ver imagen luisejr77