## Saturday, February 28, 2009

### 022609 QUIZ DAY

Hello ladies and gentlemen, how are you? I'm Jennifer, I'm scribing for Thursdays class February 26th I believe. Well on 26th we had a QUIZ on translations and corrected it in class. The quiz was posted up along with the answers by the teacher. THE END . . . . just kidding

Well I think I should go over the answers and how we got that but since my classmates are so smart. I don't think it's necessary and considering the fact that the quiz was so straight forward. But since there seemed to have been some confusion near the end of class I will try to clarify things. Since it was the quiz that confused some people, I will not reference to the quiz. Hopefully you will be able to understand after my explanations.

Stretches/ Compressions
Vertical stretches/ compressions: A vertical stretch/ compression is represented by the form of
y= af(x)
Where a is the vertical stretch factor.
Example one: Stretch x^2 by a factor of 3.

All the y-values are now higher. We just stretched the graph vertically up.

Horizontal Stretches/ Compressions: A horizontal stretch is represented by the form of
y= f(bx)
Where the reciprocal of b (1/b) is the stretch factor.
Example two: Apply f(2x)^2 to x^2
The graph has just been compressed horizontally.

Shifts
Vertical Shift; A vertical shift is represented by the form of

y= f(x) + d

Where d is the upward or down shift.

Example three: Shift x^2 up by 1 unit.

Horizontal Shift; A horizontal shift is represented by the form of

y= f(x - c)

Where c is the left or right shift.

Example four. Shift x^2 right 1 unit

NOTE: Watch the signs of your c, it is opposite.

All Together Now
af(bx - c) + d
Example five: Describe how the graph of y= -3f(x -4) +2 compares to y=f(x).
-3: reflects on the x-axis and stretched vertically by 3
4: moves f(x) right 4 units
+2: moves f(x) up by 2 units

Well that was basically what the quiz was on, translations. And as you can see near the middle of the post I came across some format problems that I just can't seem to fix ): I hope this will help you understand the mistakes that you might have made on the quiz. And if you still want me to go over the quiz I will if needed.

This took longer than I expected. I was even going to post what I have right now I was just gonna say we had a quiz, the end. But it didn't seem fair to my classmates so I did this. We do scribe on quiz days right? It was only tests that we can't scribe for.
Goodnight classmates.

The next scribe is shumei
Toddles see you all Monday!
P.S(I wonder what that stands for?) MR.K come back soon your class needs you!

#### 1 comment:

1. Nice post, Jennifer!

BTW, P.S. stands for "post script" and means something added after the body of the writing - as you did in your post.

Nice surprise for you guys Monday morning ;-).

Cheers, Dr. Eviatar.