Dive into the world of knowledge and get your queries resolved at IDNLearn.com. Get prompt and accurate answers to your questions from our experts who are always ready to help.

Which is the graph of the function [tex]f(x) = \frac{1}{2}x^2 + 2x - 6[/tex]?

A. On a coordinate plane, a parabola opens up. It goes through (-6, 0), has a vertex at (-2, -8), and goes through (2, 0).

B. On a coordinate plane, a parabola opens up. It goes through (-2, 0), has a vertex at (2, -8), and goes through (6, 0).

C. On a coordinate plane, a parabola opens up. It goes through (-4, 6), has a vertex at (4, -10), and goes through (8, -6).

D. On a coordinate plane, a parabola opens up. It goes through (-8, -6), has a vertex at (-4, -10), and goes through (4, 6).


Sagot :

To determine which graph represents the function [tex]\( f(x) = \frac{1}{2} x^2 + 2x - 6 \)[/tex], let's analyze the key features of the function step-by-step.

### Step 1: Determine the Roots of the Quadratic Function
To find the roots of the quadratic function [tex]\( \frac{1}{2} x^2 + 2x - 6 = 0 \)[/tex], we use the quadratic formula:

[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

For [tex]\( a = \frac{1}{2} \)[/tex], [tex]\( b = 2 \)[/tex], and [tex]\( c = -6 \)[/tex], we calculate:

- Discriminant:
[tex]\[ b^2 - 4ac = 2^2 - 4 \cdot \frac{1}{2} \cdot (-6) = 4 + 12 = 16 \][/tex]

- Roots:
[tex]\[ x_1 = \frac{-b + \sqrt{16}}{2a} = \frac{-2 + 4}{1} = 2 \][/tex]
[tex]\[ x_2 = \frac{-b - \sqrt{16}}{2a} = \frac{-2 - 4}{1} = -6 \][/tex]

The roots of the function are [tex]\( x_1 = 2 \)[/tex] and [tex]\( x_2 = -6 \)[/tex].

### Step 2: Determine the Vertex of the Parabola
The vertex form of a quadratic function [tex]\( ax^2 + bx + c \)[/tex] is at [tex]\( x = -\frac{b}{2a} \)[/tex]:

- Vertex [tex]\( x \)[/tex]-coordinate:
[tex]\[ x = -\frac{b}{2a} = -\frac{2}{2 \cdot \frac{1}{2}} = -2 \][/tex]

To find the [tex]\( y \)[/tex]-coordinate of the vertex, substitute [tex]\( x = -2 \)[/tex] back into the function:

[tex]\[ f(-2) = \frac{1}{2} (-2)^2 + 2(-2) - 6 = \frac{1}{2} \cdot 4 - 4 - 6 = 2 - 4 - 6 = -8 \][/tex]

So, the vertex of the parabola is at [tex]\( (-2, -8) \)[/tex].

### Step 3: Match the Features with the Given Options
The parabolas given in the options have the following features:

1. Option 1:
- Passes through [tex]\( (-6, 0) \)[/tex]
- Vertex at [tex]\( (-2, -8) \)[/tex]
- Passes through [tex]\( (2, 0) \)[/tex]

2. Option 2:
- Passes through [tex]\( (-2, 0) \)[/tex]
- Vertex at [tex]\( (2, -8) \)[/tex]
- Passes through [tex]\( (6, 0) \)[/tex]

3. Option 3:
- Passes through [tex]\( (-4, 6) \)[/tex]
- Vertex at [tex]\( (4, -10) \)[/tex]
- Passes through [tex]\( (8, -6) \)[/tex]

4. Option 4:
- Passes through [tex]\( (-8, -6) \)[/tex]
- Vertex at [tex]\( (-4, -10) \)[/tex]
- Passes through [tex]\( (4, 6) \)[/tex]

From our calculations:
- The roots are [tex]\( x = 2 \)[/tex] and [tex]\( x = -6 \)[/tex], which corresponds to passing through [tex]\( (2, 0) \)[/tex] and [tex]\( (-6, 0) \)[/tex].
- The vertex is at [tex]\( (-2, -8) \)[/tex].

### Conclusion
The correct graph must pass through [tex]\( (-6, 0) \)[/tex] and [tex]\( (2, 0) \)[/tex], and have a vertex at [tex]\( (-2, -8) \)[/tex].

Thus, the correct graph of the function [tex]\( f(x) = \frac{1}{2} x^2 + 2x - 6 \)[/tex] is described in Option 1:

> On a coordinate plane, a parabola opens up. It goes through [tex]\( (-6, 0) \)[/tex], has a vertex at [tex]\( (-2, -8) \)[/tex], and goes through [tex]\( (2, 0) \)[/tex].