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anonymous
 one year ago
A radio telescope has a parabolic surface as shown below.
A parabola opening up with vertex at the origin is graphed on the coordinate plane. The height of the parabola from top to bottom is 1 meter and its width from left to right is 8 meters.
If the telescope is 1 m deep and 8 m wide, how far is the focus from the vertex?
I will post a pic in a second.
anonymous
 one year ago
A radio telescope has a parabolic surface as shown below. A parabola opening up with vertex at the origin is graphed on the coordinate plane. The height of the parabola from top to bottom is 1 meter and its width from left to right is 8 meters. If the telescope is 1 m deep and 8 m wide, how far is the focus from the vertex? I will post a pic in a second.

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campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1well a basic form of the parabola is \[(x  h)^2 = 4a(y  k)\] (h, k) is the vertex and a is the focal length dw:1438028123648:dw so the vertex is at the origin so the equation is \[x^2 = 4ay\] substitute a point from the curve (4, 1) into the equation to find the focal length \[4^2 = 4 \times 1 \times a\] ad the the focus is a units about the vertex hope it helps

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0alright I needed some help, not for someone to write a book lol. 16 = 4 * 1 * a 16 = 4a a = 4 Now what

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh is that the answer?

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1that is the focal length, the distance from the vertex to the focus.... so if the vertex is (0, 0) the focus is at (0, 0+a)

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1well the y value in the focus is y = 4 the x value is the line of symmetry x = 0 so the focus is at (0, 4)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I am sorry, so I need the difference between the focus and the vertex, is it 4?

campbell_st
 one year ago
Best ResponseYou've already chosen the best response.1opp... sorrry you are right... I misread the question as where is the focus... the focal length is 4 so the focus is 4 metres above the vertex
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