Chapter 5: Problem 26
For the following exercises, use the vertex \((h, k)\) and a point on the graph \((x, y)\) to find the general form of the equation of the quadratic function. $$ (h, k)=(2,0),(x, y)=(4,4) $$
Short Answer
Expert verified
The quadratic function is \( f(x) = x^2 - 4x + 4 \).
Step by step solution
01
Understand the Vertex Form
The vertex form of a quadratic equation is \( f(x) = a(x - h)^2 + k \). Here, \((h, k)\) is the vertex of the parabola.
02
Substitute the Vertex Coordinates
Substitute the given vertex \((h, k) = (2, 0)\) into the vertex form equation. This gives us \( f(x) = a(x - 2)^2 + 0 \), which simplifies to \( f(x) = a(x - 2)^2 \).
03
Substitute the Point into the Equation
Use the point \((x, y) = (4, 4)\) and substitute these values into the equation to find \(a\). We have \(4 = a(4 - 2)^2\).
04
Solve for 'a'
Solve the equation \(4 = a(2)^2\). This simplifies to \(4 = 4a\). Divide both sides by 4 to find \(a = 1\).
05
Write the Equation in Vertex Form
Now that we know \(a = 1\), substitute back into the vertex form: \( f(x) = 1(x - 2)^2\), which simplifies to \( f(x) = (x - 2)^2 \).
06
Convert to General Form
Expand \((x - 2)^2\) to convert the equation to general form: \( f(x) = x^2 - 4x + 4 \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Vertex Form
The vertex form of a quadratic equation is an important concept that helps in understanding the shape and positioning of a parabola on the coordinate plane. We express it as \( f(x) = a(x - h)^2 + k \). Here,
By substituting the vertex into the vertex form, we simplify our equation to \( f(x) = a(x - 2)^2 \), indicating the parabola's vertex is at \( x = 2 \). This representation is beneficial because it visually highlights the vertex on the graph.
- \( (h, k) \) is the vertex of the parabola, which is the highest or lowest point depending on the orientation.
- The parameter \( a \) affects the width and direction of the parabola. If \( a \) is positive, the parabola opens upwards, while a negative \( a \) means it opens downwards.
By substituting the vertex into the vertex form, we simplify our equation to \( f(x) = a(x - 2)^2 \), indicating the parabola's vertex is at \( x = 2 \). This representation is beneficial because it visually highlights the vertex on the graph.
Parabola
A parabola is a U-shaped curve that represents the graph of a quadratic equation. It's symmetric around its axis of symmetry, which vertically passes through the vertex.
- The direction in which a parabola opens depends on the sign of the coefficient \( a \) in the vertex form \( f(x) = a(x - h)^2 + k \).
- If \( a > 0 \), the parabola opens upwards, resembling a smile. If \( a < 0 \), it opens downwards, looking like a frown.
General Form
Quadratic equations can also be written in general form: \( ax^2 + bx + c \). This form is derived by expanding the vertex form into a standard polynomial. It gives us another perspective on the function’s structure providing insight into roots and axis crossings.
- In this equation, \( a \) remains the leading coefficient and \( b \) and \( c \) are constants derived from expansion.
- First, expand the squared binomial: \( (x - 2)^2 = x^2 - 4x + 4 \).
- Now, our equation becomes \( f(x) = x^2 - 4x + 4 \).