Math Problem Statement

For the function​ below, (a) find the​ vertex; (b) find the axis of​ symmetry; (c) determine whether there is a maximum or a minimum value and find that​ value; and​ (d) graph the function. f(x)=2x^2+10x+11

Solution

We are given the quadratic function f(x)=2x2+10x+11f(x) = 2x^2 + 10x + 11. Let's go through the steps to answer each part of the question.

(a) Find the vertex:

The vertex form of a quadratic equation is f(x)=a(xh)2+kf(x) = a(x - h)^2 + k, where (h,k)(h, k) is the vertex. But we can find the vertex using the standard form ax2+bx+cax^2 + bx + c.

To find the x-coordinate of the vertex, we use the formula:

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

Here, a=2a = 2, b=10b = 10, and c=11c = 11. Substituting these values into the formula:

x=102(2)=104=2.5x = \frac{-10}{2(2)} = \frac{-10}{4} = -2.5

Now, substitute x=2.5x = -2.5 back into the function f(x)f(x) to find the y-coordinate of the vertex:

f(2.5)=2(2.5)2+10(2.5)+11f(-2.5) = 2(-2.5)^2 + 10(-2.5) + 11 f(2.5)=2(6.25)25+11f(-2.5) = 2(6.25) - 25 + 11 f(2.5)=12.525+11=1.5f(-2.5) = 12.5 - 25 + 11 = -1.5

Thus, the vertex is (2.5,1.5)(-2.5, -1.5).

(b) Find the axis of symmetry:

The axis of symmetry is a vertical line that passes through the x-coordinate of the vertex. From part (a), the x-coordinate of the vertex is 2.5-2.5. Thus, the axis of symmetry is:

x=2.5x = -2.5

(c) Determine whether there is a maximum or a minimum value and find that value:

Since the coefficient of x2x^2 is positive (a=2>0a = 2 > 0), the parabola opens upwards, meaning it has a minimum value at the vertex.

The minimum value is the y-coordinate of the vertex, which we found to be 1.5-1.5.

Thus, the minimum value of the function is 1.5-1.5.

(d) Graph the function:

To graph the function, follow these steps:

  1. Plot the vertex (2.5,1.5)(-2.5, -1.5).
  2. The axis of symmetry is x=2.5x = -2.5.
  3. Identify the y-intercept by evaluating f(0)f(0):

f(0)=2(0)2+10(0)+11=11f(0) = 2(0)^2 + 10(0) + 11 = 11

So, the y-intercept is (0,11)(0, 11). 4. Reflect the point (0,11)(0, 11) across the axis of symmetry to get another point (5,11)(-5, 11). 5. Connect these points to sketch the parabola, making sure it opens upwards and is symmetric about the axis of symmetry.


Would you like help visualizing this graph or need further details?

Relative questions:

  1. How can we convert a quadratic function to its vertex form?
  2. What role does the discriminant play in determining the number of x-intercepts of a quadratic function?
  3. How does the sign of the coefficient aa in a quadratic function affect its graph?
  4. What is the relationship between the vertex and the maximum/minimum value of a quadratic function?
  5. How can we solve for the roots of f(x)=0f(x) = 0 for the given quadratic function?

Tip:

For any quadratic function, the axis of symmetry always passes through the vertex, and its equation is x=b2ax = -\frac{b}{2a}.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex of a Parabola
Axis of Symmetry

Formulas

Vertex formula: x = -b / 2a
Standard form of a quadratic function: ax^2 + bx + c

Theorems

Properties of Parabolas

Suitable Grade Level

Grades 9-10