IDNLearn.com makes it easy to find accurate answers to your specific questions. Ask your questions and receive comprehensive and trustworthy answers from our experienced community of professionals.

The coordinates of the focus of the parabola −0.25x2 = y − 2 are:
A. (0, 6) B. (0, 1) C. (0, −2) D. (0, 3 )


Sagot :

The equation is [tex]-0.25x^2-x+2=0[/tex]
The coordinates are [tex](\frac{-b}{2a};\frac{-\Delta}{4a})[/tex]
[tex]\Delta=b^2-4ac=1+2=3[/tex]
The coordinates, thus, are [tex](\frac{1}{-0.5};\frac{-1}{-1})=(-2;1)[/tex]

Answer:

Option B is right.

Step-by-step explanation:

given is an equation of a parabola

[tex]-0.25x^2 =y-2\\y=-0.25x^2 +2[/tex]

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

Vertex is (0,2)

It is open down.

Axis of symmetry is x=0 or y axis

Hence focus will lie on axis of symmetry ie y axis.  

THe parabola has -4a = -4

Hence a = 1

SO focus will lie inside the parabola on axis of symmetry with a distance of a units from the vertex.

i.e. focus would equal = (0,2-1) = (0,1)

Option B is right

We greatly appreciate every question and answer you provide. Keep engaging and finding the best solutions. This community is the perfect place to learn and grow together. IDNLearn.com has the answers you need. Thank you for visiting, and we look forward to helping you again soon.