September 11, 2006

Quadratic Functions


Hello fellow students! Today we did a bit of a review from what our homework assignment was. It included stuff like finding the domain and range using interval notation and using set builders. Here's one of the questions we worked on in class (as shown above).

If the coordinate, (-2,-2), was a colored dot the domain and range would be:
Domain= (-∞,∞) Range=[-2,∞)

But since the dot is not colored the range would look like this:
Range=(-∞,-2) U (-2,∞)
The "U" means "union"(join, sum)
(This is what we call a noncontinuing function because of that one dot thats not colored)

What we spent most of the time doing in class was how to get the parabola to shift up, down, left, right, and how to make it wider. We found out that when we graph y=x² there's a straight line that runs through the coordinate (0,0) or the origin. Here are the different ways to position the parabola:

wider: y=(2/3) x²
(To make the parabola wider the numerator must be smaller than the denominator)

thiner: y=(3/2) x²
(To make the parabola thiner the numerator must be larger than the denominator)

lower: y=x-2
(The number (-2) must be a negative number to make the parabola go lower on your graph)

higher: y=x+2
(The number (2) must be a positive number to make the parabola higher)

shift to the right: y= (x-3)²
(The number (-3) must be a negative because when you square the number it becomes a positive)

shift to the left: y= (x+3)²
(The number (3) must be a positive to make the parabola shift to the left)

Our homework assignment tonight is to do all of EXCERCISE 2! I now pass on the torch for scribe to BENCHMEN! I hope you have fun with this!
SAMUS ^____^

1 comment:

  1. Hi Samus,

    And a thumbs up for the second scribe post for the semester, yours! Setting off each way to position the parabola with color and spacing made it very easy to read.

    Lani

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