SOLUTION: write an equation of the conic section parabola with vertex at (2,6) and directrix at y=8 use the discriminant to classify the conic section 9y^2-x^2+2x+54y+62=0 classify t

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: write an equation of the conic section parabola with vertex at (2,6) and directrix at y=8 use the discriminant to classify the conic section 9y^2-x^2+2x+54y+62=0 classify t      Log On


   



Question 711281: write an equation of the conic section
parabola with vertex at (2,6) and directrix at y=8
use the discriminant to classify the conic section
9y^2-x^2+2x+54y+62=0
classify the conic section and write its equation in standard form. then graph the equation
x^2+y^2+10x-12y+40=0

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
write an equation of the conic section.
..
parabola with vertex at (2,6) and directrix at y=8
This is an equation of a parabola that opens downwards.
lts standard form: %28x-h%29%5E2=-4p%28y-k%29, (h,k)=(x,y) coordinates of the vertex (2,6)
axis of symmetry: x=2
p=2, (distance between vertex and directrix on the axis of symmetry)
4p=8
Equation: %28x-2%29%5E2=-8%28y-6%29
..
use the discriminant to classify the conic section
9y^2-x^2+2x+54y+62=0
9y^2+54y-x^2+2x=-62
complete the square:
9(y^2+6y+9)-(x^2-2x+1)=-62+81-1
9(y+3)^2-(x-1)^2=18
Equation: %28y%2B3%29%5E2%2F2-%28x-1%29%5E2%2F18=1
This is an equation of a hyperbola with vertical transverse axis and center at (1,-3)
Its standard form: %28y-k%29%5E2%2Fa%5E2-%28x-h%29%5E2%2Fb%5E2=1, (h,k)=(x,y) coordinates of center
..
classify the conic section and write its equation in standard form. then graph the equation
x^2+y^2+10x-12y+40=0
x^2+10x+y^2-12y=-40
complete the square:
(x^2+10x+25)+(y^2-12y+36)=-40+25+36
%28x%2B5%29%5E2%2B%28y-6%29%5E2=21
This is an equation of a circle with center at (-5,6) and radius=√21
Its standard form: %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2 , (h,k)=(x,y) coordinates of center, r=radius
see graph below:
y=±(21-(x+5)^2)^.5+6