Question

The graph of a quadratic function is called a(n) _____________.

Short answer

parabola

Step-by-step solution

Understand the Form of a Quadratic Function

A quadratic function can be written in the standard form: \( f(x) = ax^2 + bx + c \), where \(a\), \(b\), and \(c\) are constants and \(a eq 0\).

Identify the Shape of the Graph

The graph of a quadratic function is a special type of curve known for its specific shape. This shape is symmetric around its vertex.

Name the Shape

The shape of the graph of a quadratic function is called a parabola. This is due to its characteristic U-shaped curve.

Key concepts

parabola

A parabola is the graph of a quadratic function and has a distinct, U-shaped curve. This curve is key to many real-world phenomena like the path of a projectile or the shape of satellite dishes.
Parabolas have several interesting properties:

• They can open upwards or downwards depending on the sign of the coefficient ‘a’ in the quadratic function.
• If ‘a’ is positive, the parabola opens upwards and forms a shape like a valley. If ‘a’ is negative, it opens downwards, resembling a hill.
• Every parabola is symmetric about a vertical line through its vertex, known as the axis of symmetry.

The vertex represents the maximum or minimum point of the parabola, depending on its direction.
Understanding parabolas helps in various fields such as physics, engineering, and economics.

standard form of quadratic function

The standard form of a quadratic function is crucial for analyzing its graph and solving related problems. The function is expressed as:
\[ f(x) = ax^2 + bx + c \]
where ‘a’, ‘b’, and ‘c’ are constants and ‘a’ is not equal to zero. Here's what each term represents:

• The coefficient ‘a’ determines the direction and width of the parabola. A larger absolute value of ‘a’ results in a narrower parabola.
• The coefficient ‘b’ affects the position of the vertex along the x-axis.
• The constant ‘c’ represents the y-intercept, where the parabola crosses the y-axis.

By analyzing the standard form, you can determine important characteristics of the quadratic function, such as:

• The vertex of the parabola
• The axis of symmetry
• The direction of the parabola's opening

This form is instrumental in graphing the function and understanding its geometric properties.

symmetric vertex

The vertex of a parabola is a significant point that reflects its symmetry. It is the peak if the parabola opens downwards or the lowest point if it opens upwards.
The axis of symmetry passes through the vertex, dividing the parabola into two mirror-image halves. To find the vertex of a quadratic function in standard form:

• Use the formula to find the x-coordinate of the vertex:
  
  \[ x = -\frac{b}{2a} \]<\br>This formula comes from completing the square on the quadratic equation.
• Substitute this x-value back into the original quadratic function
  \[ f(x) = ax^2 + bx + c \]
  to find the y-coordinate.

With both coordinates, you have the vertex
\( (x, y) \) .
For example, for the quadratic function \( f(x) = 2x^2 - 4x + 1 \), the x-coordinate of the vertex is \( x = \frac{4}{4} = 1 \). Plugging this back into the function gives the y-coordinate as \( f(1) = -3 \). So, the vertex is
\( (1, -3) \).
Understanding the vertex is essential for graphing the quadratic function and making sense of its symmetrical properties.