How can I determine a parabola given two points?

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In summary, it is not possible to determine an explicit equation for a parabola with only two arbitrary points. The general form of a parabola is y=ax^2+bx+c, but this is not enough to find the values of a, b, and c. If additional information about the points is given, it may be possible to find a specific equation. However, if the goal is to find a parabola that goes through the given points, substituting them into the general form will result in simultaneous equations with multiple solutions.
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dtl42
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If given two arbitrary points on a parabola, is there anyway to determine an explicit equation for that parabola. I know there are multiple possible parabolas, but how can I find just one of them?
 
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  • #2
the general form of a parabola is [itex]y=ax^2 +bx+c[/itex]

so given two points on the parabola, that would be insufficient to find a,b and c. If there is something else given about those 2 points then you may be able to find it.
 
  • #3
If given two points, and you want the family of parabolas to go through them, just substitute those points into the general form of a parabola and you should get some simultaneous equations. You won't able able to get unique solutions for them, as you know, because there are many parabolas that go through those 2 points. If you want just any, choose any solution to the equations.
 

Related to How can I determine a parabola given two points?

1. What is a parabola?

A parabola is a symmetrical U-shaped curve that can be formed by graphing a quadratic equation. It is a type of conic section and is characterized by its vertex, focus, and directrix.

2. How do you determine the vertex of a parabola?

The vertex of a parabola is the point where the curve changes direction. It can be determined by finding the axis of symmetry, which is a vertical line that passes through the vertex. The x-coordinate of the vertex can be found by using the formula x = -b/2a, where a and b are the coefficients of the quadratic equation in standard form.

3. What is the focus of a parabola?

The focus of a parabola is a fixed point inside the curve that is equidistant from every point on the parabola. It can be found by using the formula (h+k)/2, where h and k are the x and y coordinates of the vertex.

4. How do you find the directrix of a parabola?

The directrix of a parabola is a line perpendicular to the axis of symmetry that is also equidistant from every point on the curve. It can be found by using the formula y = k - p, where p is the distance between the vertex and focus.

5. What is the significance of a parabola in real-life applications?

Parabolas are commonly used in physics and engineering to model the trajectory of projectiles, such as projectiles launched from a cannon or a ball thrown in the air. They can also be used to model the shape of satellite dishes, reflectors, and other curved structures in architecture and design.

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