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# Analytical geometry

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1-Find the vertex focus, and directrex of the parabola=
1-x2= 2 (x+y)

2-Write an equation of the vertical parabola that contains (-1,2) with focus (3,1) and which opens upward.

3-Write an equation for the parabola that has vertex (1,2) and its axis is parallel to the x-axis, passes through the point (13,4)

4-Find all elements of the given ellipse and sketch the following equation: 25x2 + 9y2 - 100x +108 y + 199=0

5-Find the equation of the ellipse given that vertices (-8,0) and (8,0) with minor axis= 6

6-Write the equation of the ellipse given vertices are V (8,3) and V' (-4,3), one focus (6,3).

https://brainmass.com/math/analytic-geometry/vertex-focus-directrix-parabola-14884

#### Solution Preview

Q1-find the vertex focus, and directrix of the parabolas =
Ans: 1-x2= 2(x+y) = 2x + 2y
Or x2 + 2x - 1= -2y
Or x2 + 2x + 1 - 2 = -2y
Or (x+1)2 = 2 - 2y = -4*0.5(y-1)
Or X2 = -4aY, where X = x+1, Y = y-1, a = 0.5
This is a parabola which opnes downwards with the vertex at (-1, 1).
The focus is at (0, -a) = (0, -0.5)
The directrix is y = a, or y = 0.5.

2-Write an equation of the vertical parabola that contains (-1,2) with focus (3,1) and which opens upward.
Ans: Since the parabola opens upwards, x should be squared and y should be linear.
If the equation of the parabola is of the type X2 = 4aY, then
Focus : X = 0, Y = a
Vertex: X = 0, Y = 0
Let X = x-h, Y = y-k, where the vertex is at (h, ...

#### Solution Summary

The expert finds the vertex focus and directrix of the parabola. Elements of the given ellipse of equations are found.

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