Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
2. Properties of Rational Exponents and Radicals
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Exercise 83 Page 250

Which variable is raised to the second power? Does it mean that the axis of symmetry of the parabola is a horizontal or a vertical line?

Focus: ( - 14,0 )
Directrix: x= 14
Axis of Symmetry: y=0

Graph:
Practice makes perfect

Before we begin, note that in the given equation the variable that is raised to the second power is y. y^2=- x Therefore, the axis of symmetry of the parabola is a horizontal line.

Finding the Desired Information

Let's recall the general form of a parabola whose axis of symmetry is a horizontal line. 1/4 p(y- h)^2+ k=x In order to match this form perfectly, let's rewrite our equation a bit. y^2=- x ⇔ - 1y^2=x We need to identify the values of h, k, and p. Let's start with p. To do so, we will solve the equation 14 p=- 1. We set it equal to - 1 because - 1 is the coefficient of y^2.
1/4p=- 1
â–Ľ
Solve for p
1=- 4p
- 1/4=p
p=- 1/4
Knowing that p= - 14, we can rewrite the equation. y^2=- x ⇕ 1/4( - 14 ) (y - 0)^2 + 0= x Now we have that h= 0, k= 0, and p= - 14. By recalling the corresponding formulas, we can find the vertex, focus, directrix, and axis of symmetry of the parabola.
Vertex Focus Directrix Axis of Symmetry
Formula ( h, k) ( h+ p, k) x= h- p y= k
Value ( 0, 0) ( 0+( - 1/4), 0)
⇕
( - 1/4,0 )
x= 0-( - 1/4)
⇕
x=1/4
y= 0

Drawing the Parabola

Now, let's draw the parabola using the obtained information.