With just a few scrolls, learn all about Quadratics!
The Importance of Quadratics
Intro to Quadratics
- Analyzing properties of a Parabola
- Second Difference
- Step Pattern
- How to use Algebra Tiles (A quadratic relations rookie's life saver)
- Expanding Binomials
- Common Factoring
- Factoring Simple Trinomials
- Factoring Complex Trinomials
- Special Cases (Perfect Squares, Difference of Squares)
- Factoring by Grouping
- Graphing Factored Form
- Effects of Vertex form
- Isolating X
- Determining (a) value (given a point and vertex)
- Graphing Vertex Form
- Completing the Square
- Solving with Quadratic Equation
- Finding the Axis of Symmetry (x value of the vertex)
- Graphing Standard Form
- Motion Problems
- Area Problems
(My thoughts on the unit)
Lets Get Started!
Anaylzing the properties of a Parabola
Vertex- where the optimal value and the axis of symmetry meet
Axis of symmetry- the half line of the curve (vertical line)
Optimal Value- the highest or lowest point of the parabola (horizontal line)
y-intercept- the point when the curve crosses the y-axis ( all numbers above optimal value y< and all numbers below optimal value y>
x-intercepts/roots/zeros- the points where the curves cross the x-axis (all real numbers)
The step pattern is applied in all graphs. The step pattern helps determine where each of the points of the graph are going to be. The points on the graph will always be affected by the (a) value in your equation. If there is no a value, then you are to use to original pattern, however, if there is an a value, that value will be multiplied to each value in the original step pattern chart. Refer to the video.
An equation written in Factored Form is written as y=a(x+r)(x+s)
The (r) and the (s), represent the x-intercepts when graphed.
The vertex is written as (x,y) meaning (Axis of symmetry, y-intercept), once the values have been found
The (a) value is multiplied to the step pattern, to determine the coordinates on the graph
For beginners and visual learners, algebra tiles are a great and effective way that can solve for quadratic relations. Refer to video.
Learning to Expand binomials, basically going from factored form to standard form is very important. this transition makes it much easier to graph the equation in vertex form. Refer to the video in order to see the step by step process of expanding binomials. Refer to the video to learn how expanding binomials is done.
Common FactoringThere are many different ways that you can factor an equation. For learning about any method of factoring, it is important that you know how to common factor. Refer to the video.
(Possibly the easiest of the bunch)
Complex Trinomials uses the guess and check chart. The first set of numbers that multiply to your first number in your expression are cross multiplied with whatever two other numbers that can be multiplied to equal your third number in your expression. Then, in order to determine whether the pairs equal the final expression, simply add the two numbers in the last column of the guess and check chart. If the two added numbers equal the second number in your expression, you have found your answer. Refer to the video
Perfect Square- Three numbers in the expression, First number and third number can be square rooted. In order to prove if the expression is a perfect square, multiply your square rooted numbers results together, then multiply them by 2. If the answer ends up adding to the second number in your original expression, you have solved your perfect square correctly.
4x2 square rooted= 2x
9 square rooted= 3
Difference of squares- Two numbers in the expression. Both numbers can be square rooted, however, second number is negative.
Note that factor by grouping can only be done when there are four numbers in the expression, making it very easy to determine how you will be solving the expression.
When working with Factored form, the equations will always look as such: y=a(x+r)(x+s)
If the equation is not given in factored form, determine what type of factoring (simple trinomial, complex trinomial, difference of squares e.t.c) must be done to the equation, and bring the equation to Factored form y=a(x+r)(x+s)
An equation in Vertex Form is written as such; y=a(x-h)2+k
The (h) and (k) value represent the Vertex. It is written as (h,k) representing (Axis of symmetry, y-intercept).
The (a) value is multiplied to the step pattern in order to determine the coordinates on the graph.
The x-intercepts are represented by (x,y)
Effects of Vertex Form (Properties of Vertex Form)
The (-h) moves the vertex of the parabola left or right. Keep in mind that if the (h) is negative, it is to be moved right, and when the (h) is positive, it is to be moved left.
This horizontal shift, affects the axis of symmetry.
The (k) moves the vertex up or down. Keep in mind that if the (k) is positive, it is to be moved up, and if the (k) is negative, it is to be moved down. This vertical shift affects the optimal value.
The (a) is a vertical stretch or compression. if the (a) is positive, the parabola will open up, if the (a) is negative, the parabola will open down.
The vertex in vertex form is made up of h and k and is written as (h,k).
Isolating x is used in vertex form when trying to find the x-intercepts of the equation. The steps below show the steps that need to be taken in order to find the zero's (x-intercepts).
Note that the original equation for every equation in vertex form is written as
In vertex form the a value highly impacts where the points of the graph will be as the a value is multiplied to the step pattern. However in certain equations, the (a) value, will not always be given. In these circumstances, the equation will always have a point (x,y) and the vertex (h,k). Down below there is an example of how you can isolate the (a), in order to find its value.
Graphing Vertex Form is the easiest out of the three. In the different subsections above, you can see the different situations the an equation of vertex form can be in. Always keep in mind the the equation of Vertex form is y=a(x-h)2+k. Here is a video, that will show you how to graph Vertex form.
A Standard form equation is written as y=ax2+bx+c
A standard form equation can also be written as ax2+bx+c=0 < meaning that the y has been turned into a zero
Completing the Square
Completing the square is a quick and easy way to transform a Standard form equation into a Vertex Form equation. This is helpful as graphing in Vertex form is known to be the easiest of the three ways. In order to complete a square, you must know how to factor perfect squares. Refer back to the Perfect squares video in the Factored form section to refresh your memory on how to complete a square.
*Keep in mind, a Perfect square consists of three numbers (ax2+bx+c) where the first and second number can be square rooted, and the results of the square rooted numbers multiplied together, then also multiplied with 2 are equal to the second number in the equation.
Watch the video below to learn how to complete a square.
Quadratic Equation is used on Standard form equations, if the equation is not easily factor-able, meaning that a number that needs to be factored, would result with a decimal.
Discriminant is apart of the Quadratic Equation of which it allows us to determine how many solutions (x-intercepts) a curve will have, when plotted on a graph. This is found within the quadratic formula
Finding the Axis of Symmetry (x value of vertex)
In order to find the x value of the vertex use the formula -b/2(a)
Example: a=3 b=3 c=3 x= -3/2(3)
x= -0.5 --------> (-0.5, 0) is the x value of the vertex
Graphing Standard Form
Now that you have been introduced to all things quadratics, wrapping the whole unit together with word problems is a great way to tie all the pieces together.
Motion Problems Focus on collecting data on the height and time of a curve. This can be represented by a roller coaster in our everyday life, if you were to calculate the amount of time it took a cart to go up a ramp, and come back down. This video will show you how a motion problem can be solved.