7 articles trouvés pour ce sujet.
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The parabola with vertex (7,-2) and directrix y = -3 |
2009-01-21 |
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Deann pose la question :
Find an equation of the parabola with vetrex (7,-2) and directrix y =(-3)
Penny Nom lui répond. |
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The foci of an ellipse |
2007-03-27 |
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Brad pose la question :
I am trying to figure out how to find the foci of an ellipse x^2/7 + y^2/16 = 1.
Since 16 is the largest denominator I know the major axis is going to be the y axis.
Do I now take 7-c^2=16. c^2=16-7, c^2=9, c=3. So is my foci (0,+-3).
Penny Nom lui répond. |
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The focus of a parabola |
2006-10-01 |
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Lily pose la question :
I have a mathematical assignment which includes applications of parabolas, hyperbolas and ellipses in the real world. I have been searching the internet and now I am ware that most of the applications of parabolas have a connection with what people call "the focus". However, I do not think I clearly understand what "the focus" of a parabola is. Would you please explain it to me?
Penny Nom lui répond. |
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Parabolic mirrors |
1999-11-07 |
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Andy White pose la question :
I am working on a project concerning parabolic mirrors. I need to create a mirror to focus sunlight on a focal point, but I don't know how to do it. Is there some equation that tells where a focal point will be in relation to a parabola? What is a directrix?
Penny Nom lui répond. |
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Parabolas |
1998-07-24 |
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Danica pose la question :
how do you find the focus, vertex, and directrix of 4x-y^2-2y-33=0
Penny Nom lui répond. |
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Parabolic Mirrors |
1997-01-28 |
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Megan Wennberg pose la question :
Consider a ray of light that passes through a chord of a parabola (the chord is above the focus and parallel to the directrix), hits the parabola at a point (x,y) and is reflected through the focus. If d1 is the distance from the chord to the point of incidence (x,y) and d2 is the distance from (x,y) to the focus, can you prove that the sum of the distances d1+d2 is constant, independent of the particular point of incidence.
Penny Nom lui répond. |
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Foci of an Ellipse |
1997-01-22 |
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David Gilliam pose la question :
How do I find the focii of the following equation? 4x^2 + 9y^2 = 36
Harley Weston lui répond. |
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