The Quadratic Function and Its Properties

Oct 13, 2025 by wbrum.org 134 views

Introduction

In mathematics, a function is a relation between a set of inputs, called the domain, and a set of possible outputs, called the range. A quadratic function is a polynomial function of degree two, which means the highest power of the variable is two. The general form of a quadratic function is given by $$f(x) = ax^2 + bx + c$$, where $$a$$, $$b$$, and $$c$$ are constants. In this article, we will explore a specific quadratic function defined by $$f: x \rightarrow ax^2 + bx + 1$$, and we will use the given conditions $$f(1) = 0$$ and $$f(-1) = 0$$ to find the values of $$a$$ and $$b$$.

The Quadratic Function and Its Properties

The quadratic function $$f(x) = ax^2 + bx + 1$$ is a polynomial function of degree two. The graph of this function is a parabola, which is a U-shaped curve. The parabola opens upwards if $$a > 0$$ and downwards if $$a < 0$$. The vertex of the parabola is the point where the function changes from increasing to decreasing or vice versa.

Using the Given Conditions to Find the Values of a and b

We are given that $$f(1) = 0$$ and $$f(-1) = 0$$. This means that when we substitute $$x = 1$$ and $$x = -1$$ into the function, we get zero. We can use this information to set up a system of equations and solve for $$a$$ and $$b$$.

Substituting x = 1 into the Function

When we substitute $$x = 1$$ into the function, we get:

f(1) = a(1)^2 + b(1) + 1 = 0

Simplifying this equation, we get:

a + b + 1 = 0

Substituting x = -1 into the Function

When we substitute $$x = -1$$ into the function, we get:

f(-1) = a(-1)^2 + b(-1) + 1 = 0

Simplifying this equation, we get:

a - b + 1 = 0

Solving the System of Equations

We now have a system of two equations with two unknowns:

a + b + 1 = 0

a - b + 1 = 0

We can solve this system of equations by adding the two equations together:

(a + b + 1) + (a - b + 1) = 0 + 0

Simplifying this equation, we get:

2a + 2 = 0

Subtracting 2 from both sides, we get:

2a = -2

Dividing both sides by 2, we get:

a = -1

Finding the Value of b

Now that we have found the value of $$a$$, we can substitute it into one of the original equations to find the value of $$b$$. We will use the first equation:

a + b + 1 = 0

Substituting $$a = -1$$, we get:

-1 + b + 1 = 0

Simplifying this equation, we get:

b = 0

Conclusion

In this article, we have explored a specific quadratic function defined by $$f: x \rightarrow ax^2 + bx + 1$$. We have used the given conditions $$f(1) = 0$$ and $$f(-1) = 0$$ to find the values of $$a$$ and $$b$$. We have found that $$a = -1$$ and $$b = 0$$. This demonstrates the power of using given conditions to solve for unknown values in a quadratic function.

Final Answer

The final answer is:

$a = -1$
$b = 0$$<br/>$

Introduction

In our previous article, we explored a specific quadratic function defined by $$f: x \rightarrow ax^2 + bx + 1$$, and we used the given conditions $$f(1) = 0$$ and $$f(-1) = 0$$ to find the values of $$a$$ and $$b$$. In this article, we will answer some frequently asked questions related to the quadratic function and its properties.

Q&A

Q: What is the general form of a quadratic function?

A: The general form of a quadratic function is given by $$f(x) = ax^2 + bx + c$$, where $$a$$, $$b$$, and $$c$$ are constants.

Q: What is the graph of a quadratic function?

A: The graph of a quadratic function is a parabola, which is a U-shaped curve. The parabola opens upwards if $$a > 0$$ and downwards if $$a < 0$$.

Q: What is the vertex of a parabola?

A: The vertex of a parabola is the point where the function changes from increasing to decreasing or vice versa.

Q: How do we find the values of $$a$$ and $$b$$ in a quadratic function?

A: We can find the values of $$a$$ and $$b$$ by using the given conditions and setting up a system of equations. In our previous article, we used the conditions $$f(1) = 0$$ and $$f(-1) = 0$$ to find the values of $$a$$ and $$b$$.

Q: What is the value of $$a$$ in the quadratic function $$f(x) = ax^2 + bx + 1$$?

A: We found that the value of $$a$$ is $$-1$$.

Q: What is the value of $$b$$ in the quadratic function $$f(x) = ax^2 + bx + 1$$?

A: We found that the value of $$b$$ is $$0$$.

Q: How do we determine the direction of the parabola?

A: We can determine the direction of the parabola by looking at the value of $$a$$. If $$a > 0$$, the parabola opens upwards. If $$a < 0$$, the parabola opens downwards.

Q: What is the significance of the vertex of a parabola?

A: The vertex of a parabola is significant because it represents the minimum or maximum value of the function.

Conclusion

In this article, we have answered some frequently asked questions related to the quadratic function and its properties. We have discussed the general form of a quadratic function, the graph of a quadratic function, the vertex of a parabola, and how to find the values of $$a$$ and $$b$$ in a quadratic function. We have also determined the value of $$a$$ and $$b$$ in the quadratic function $$f(x) = ax^2 + bx + 1$$.

Final Answer

The final answer is:

$a = -1$
$b = 0$

Additional Resources

For more information on quadratic functions, please refer to our previous article: "A Function Defined by a Quadratic Equation: Finding the Values of a and b"
For more information on the graph of a quadratic function, please refer to the following resources:
- Khan Academy: Quadratic Functions
- Mathway: Quadratic Functions
For more information on the vertex of a parabola, please refer to the following resources:
- Wolfram MathWorld: Vertex of a Parabola
- Math Open Reference: Vertex of a Parabola