{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Stitz-Zeager_College_Algebra_e-book

# As before the b a2 distance d is the length of the

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: −2). We also see that 4p = −8 so that p = −2. Since p < 0, the focus will be the left of the vertex and the parabola will open to the left. The distance from the vertex to the focus is |p| = 2, which means the focus is 2 units to the left of 1, so if we start at (1, −2) and move left 2 units, we arrive at the focus (−1, −2). The directrix, then, is 2 units to the right of the vertex, so if we move right 2 units from (1, −2), we’d be on the vertical line x = 3. Since the focal diameter is |4p| is 8, the parabola is 8 units wide at the focus, so there are points 4 units above and below the focus on the parabola. y 2 1 −2 −1 −1 1 2 x −2 −3 −4 −5 −6 In studying quadratic functions, we have seen parabolas used to model physical phenomena such as the trajectories of projectiles. Other applications of the parabola concern its ‘reﬂective property’ which necessitates knowing about the focus of a parabola. For example, many satellite dishes are formed in the shape of a para...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern