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The road to success is always under construction!!

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Presentation on theme: "The road to success is always under construction!!"— Presentation transcript:

1 The road to success is always under construction!!

2  To graph parabolas what do you think the single most important point is that you should know?  THE VERTEX  It gives you a home base to work off of.

3  Once you identify your vertex, it is important that you plot at least four other points.  Where should these points be?  At least two should go on either side.

4  To decide this, the easiest thing to do is use the step pattern.  What is the step pattern?  The step pattern is the pattern which tells you how much to go up or down for every one unit that you go over.  The step pattern is based off of the first differences in a quadratic.

5  In the most basic quadratic y=x 2 the first differences are 1,3,5  IMPORTANT  This means that for any parabola with an “a” of 1 or -1, it will follow the 1,3,5 step pattern.  You should memorize this!!

6 Ex. Graph the following parabolas on the given grid a)y=x 2 b)Y=-x 2

7  This is easy.  All we do is multiply the 1,3,5 step pattern by whatever the new “a” value is  For example if you have y=2x 2, the step pattern would be 2,6,10  For y = 0.5x 2, the step pattern would be 0.5,1.5,2.5  What would the step pattern be for y=3x 2

8 Graph the following on the grid provided Ex. 1.y=2x 2 2.Y=0.5x 2 3.Y=-2x 2

9  So what if we get an equation with all of the transformations?  Ex y=2(x-3) 2 -4  Steps:  1. Find the vertex  2. Apply the step pattern

10 Graph: y=2(x-3) 2 -4

11  Do you still use the step pattern?  Probably NOT.  In cases like this it is better to use a table of values.

12  Graph f(x)=0.37(x+4) 2 -3  Step 1. Plot the vertex  Step 2. Choose two values to plug in for x and then to solve for y.

13  I’ll choose to plug in -3 and -2 for x  F(-3)=-2.63. This means when I go one to the right of the vertex, the y value is -2.63  By symmetry I also know that if I go one to the left of the vertex f(-5) =-2.63

14  Now go two to the right of the vertex.  F(-2)=-1.52. This means when I go two to the right of the vertex the y value is -1.52  By symmetry if I go two to the left of the vertex, f(-6)=-1.52

15

16  For most parabolas you can simply use the step pattern and finish the graph very quickly  If the numbers involve long strings of decimals a table of values is probably more appropriate.


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