Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
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Exercise 3 Page 87

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: ( 1/8, 0 )
Directrix: x=- 1/8
Axis of Symmetry: y=0

Practice makes perfect

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

Finding the Desired Information

Let's recall the general form of the equation for this type of parabola. x=1/4 p(y- k)^2+ h We need to identify the values of p, k, and h. Let's start with p. To do so, we will solve the equation 14 p=2. We set it equal to 2 because 2 is the coefficient of the parenthetical factor.

1/4p=2
Solve for p
1=8p
1/8=p
p=1/8

Knowing that p= 18, we can rewrite the equation. x=2y^2 ⇕ x=1/4( 18 ) (y- 0)^2+ 0 Now we have that p= 18, k= 0, and h= 0. By recalling the corresponding formulas, we can find the focus, directrix, and axis of symmetry of the parabola.

Focus Directrix Axis of Symmetry
Formula ( h+ p, k) x= h- p y= k
Value ( 0+ 1/8, 0) ⇒ ( 1/8,0 ) x= 0- 1/8 ⇒ x=- 1/8 y= 0

Drawing the Parabola

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