Math Problem Statement

For the quadratic function f left parenthesis x right parenthesis equals negative 2 x squared plus 2 x minus 6​, answer parts​ (a) through ​(f). Question content area bottom left Part 1 ​(a) Find the vertex and the axis of symmetry of the quadratic​ function, and determine whether the graph is concave up or concave down. The vertex is

enter your response here.

Solution

The given quadratic function is:

f(x)=2x2+2x6f(x) = -2x^2 + 2x - 6

Step 1: Identify whether the graph is concave up or concave down.

The coefficient of x2x^2 is 2-2, which is negative. Therefore, the parabola opens downward, meaning the graph is concave down.

Step 2: Find the axis of symmetry.

For a quadratic function in the form f(x)=ax2+bx+cf(x) = ax^2 + bx + c, the formula for the axis of symmetry is:

x=b2ax = \frac{-b}{2a}

Here, a=2a = -2 and b=2b = 2. Substituting these values:

x=22(2)=24=12x = \frac{-2}{2(-2)} = \frac{-2}{-4} = \frac{1}{2}

Thus, the axis of symmetry is x=12x = \frac{1}{2}.

Step 3: Find the vertex.

To find the vertex, substitute x=12x = \frac{1}{2} into the quadratic function f(x)f(x) to find the corresponding yy-coordinate.

f(12)=2(12)2+2(12)6f\left(\frac{1}{2}\right) = -2\left(\frac{1}{2}\right)^2 + 2\left(\frac{1}{2}\right) - 6

Simplifying:

f(12)=2(14)+2(12)6f\left(\frac{1}{2}\right) = -2\left(\frac{1}{4}\right) + 2\left(\frac{1}{2}\right) - 6 =24+16=12+16=126=112= -\frac{2}{4} + 1 - 6 = -\frac{1}{2} + 1 - 6 = \frac{1}{2} - 6 = -\frac{11}{2}

Thus, the vertex is (12,112)\left(\frac{1}{2}, -\frac{11}{2}\right).

Final Answer:

  • The vertex is (12,112)\left(\frac{1}{2}, -\frac{11}{2}\right).
  • The axis of symmetry is x=12x = \frac{1}{2}.
  • The graph is concave down.

Would you like more details or have any questions? Here are 5 follow-up questions to explore this further:

  1. How do you find the y-intercept of a quadratic function?
  2. What is the significance of the vertex in a quadratic graph?
  3. Can you derive the formula for the vertex from completing the square?
  4. How does the sign of the leading coefficient affect the shape of the parabola?
  5. What are the properties of the axis of symmetry in any quadratic function?

Tip: The vertex form of a quadratic equation can make finding the vertex much easier!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex Form
Parabola

Formulas

Axis of symmetry: x = -b / 2a
Vertex form of a quadratic equation
f(x) = ax^2 + bx + c

Theorems

The Axis of Symmetry Theorem
Concavity of Quadratic Functions

Suitable Grade Level

Grades 8-10