Quadratic 101
By Harry G
Learning goals
- I will learn how to transfer vertex equation on to a graph using one of the transformation.
- I will understand how vertex equations work.
- I will learn the difference between 1st and 2nd difference
- I will learn how to isolate to solve for a variable
what is Vertex form?
Vertex Form is a equation that you can use to solve quadratic relations.
- The equation to describe this is y=a(x-h)+k.
- The value H gives you information on the X value of the Vertex of the relation and the horizontal translation from the origin.
- The value A gives you information on which way the graph faces and its shape.
- Finally the value K gives you information on the y value of the Vertex and the vertical translation from origin.
1st and 2nd differences
Step Pattern
- Identify and plot the Vertex (H,K)
- Determine the step pattern (1a, 3a, 5a, 7a, etc)
- Plot the step points (over 1 up/down 1a, over 1 up/down 3a, over 1 up/down 5a)
- Reflect each point across the axis of symmetry
- Draw a curve between points
Example
Mapping Notation
Mapping Notation is another way of figuring out the points to sketch your graph. What you need for this is:
Your equatuation in Vertex Form
The formula (x+h, ay+k)
and a table showing you the points of y=x^2
As you already know, Vertex Form is y=a(x-h)^2+k. To do Mapping Notation, what you need to do is sub the values of your equation, into the formula (x+h, ay+k). This means that if you had an equation like (y=2(x-3)^2+5) your formula would look like this (x+3, 2y+5). this is because (a=2, h=3 and k=5). Now all you have to do is take the x values from the table that shows you the points of y=x^2 and sub them inot the mapping notation formula. (for example i would take -3 and sub it into the x part of the formula [-3+3] and the 9 into the y part of the formula [2*9+5]. This gives you your x and y coordinates (make sure that while you are subbing the points, you are making another table on the sides which clearly show what the x and y values are). you will continue to do this until you get the next 5-7 coordinates.
Video on How to use Mapping Notation
Transformation
The transformations in the an equation that is in Vertex form are: a(x-h)^2+k
(-)A - if a is negative then the Direction of Opening will be down and if a is positive then the Direction of Opening will be up.
H - The h in Vertex form represents the Horizontal Translation left or right.
K - the k in Vertex form represents the Vertical Translation up or down.
Word Problem
How to isolate for a variable,
Factoring
Learning goals
2. I will learn how to convert from standard form to factored form
3. I will learn how to solve word problem using factored form
4. I will learn how to factor Perfect squares, difference of square and how to complete a square
Table of content
Expanding and Simplifying
- Factoring Standard Form
- Common Factoring
- Factoring by Grouping
- Simple Trinomials
- Complex Trinomials
- Difference of Squares
- Perfect Squares
- Completing the Square
Summary of the units
Factoring is the method to simplify an expression. There are multiple types of factoring including common factoring, factoring simple trinomials, factoring complex trinomials, prefect squares, and difference of squares.
Key things to know before we start:
- The value of a gives you the shape and direction of opening
- The value of r and s give you the x-intercepts
- Solve using the factors
Common factoring
Factoring By Grouping
Simple Trinomial
Complex Trinomials and How to factor them
Completing the Square
Perfect Square
How to Factor Perfect Squares
An example:
100x^2+60+9
*100 square rooted is 10 and the square root of 9 is 3
*2(10)(3)=60
*(10x+3)^2
*To check if your final answer is correct, when you expand your answer(in this case) (10x+3)^2 into (10x+3)(10x+3) and then multiply both brackets (using F.O.I.L), you should end up with the original equation (in this case) 100x^2+60+9
Difference of Square
Factoring the difference of squares
Example:
x^2-49
*the square root of 1(x) is 1 and the square root of 49 is 7
*(x+7)(x-7)
*Multiply both brackets(F.O.I.L) to find out if the answer is correct
*x^2-7x+7x-49 (collect like terms)
*x^2-49 therefore (x+7)(x-7) is the correct answer in this case
Word Problem using factored form
Standard Form
Learning Goals
2. I will understand how to solve using completing the squares to find the vertex
3. I will learn how to solve word problems
Summary
Quadratic equation example
Completing the square
Word Problem
Quadratic formula word problem
Similarities between all 3 form of quadratics
Vertex form
- By setting a value to 0 (ex x=o) you are able to find the other (ex. x=0 and y can be determined by setting x to 0)
- Able to be turned into standard form simply by expanding
- Standard form is expressed as y=ax^2+bx+c
- Is able to be turned into factored form (only in certain cases)
- When changed into a perfect square it then is in vertex form
- Is able to be changed into standard form by expanding
- (A 2 step process) can be changed into standard form then vertex form
The word problems in all the form of quadratics were mostly asking for the same thing just in different forms of equations and different methods.
All three form of quadratics can be graphed, to graph them you need the same thing (X,Y and their intercepts) Once graphed all of them make a parabola.
if we use the quadratic formula we can solve to get x and then we can graph the equation while in vertex form.
Reflection
Throughout the course we looked at 3 different units each one relating to the other. I found it difficult to understand how to graph the parabola at first for all of them, or even solving for the vertex. The most difficult part was understanding how to do the word problems, in the way they were written sometimes the wording of the problem would confuse me and i would just mess up. I also found it difficult to isolate for a specific variable, something which i struggled with in every unit of quadratics. Besides all of the difficult things one of the easiest parts in quadratics was using mapping notation to graph the parabola, this part i found to be extremely easy because using the step pattern my teacher taught me, i just need to know the a value and times that by 1 and then 3 and then 5, once i have this i could just graph it move over which ever direction and then graph that point and keep doing this until i have a shape of parabola.