Sample Problems, Lesson 1.3
Sample Problems for this Lesson Course Home Page To the Notes Menu   Assignment  

1.3, Problem #2
Explain how the following graphs are obtained from the graph of 

Problem
Answer
Explanation
(a)   This function will be 5 times "steeper" than the original, . This is a stretching transformation
(b)   This function will be shifted 5 units to the right. This is a translation (or lateral translation). 
(c)   This function will be the mirror image of  with respect to the x-axis. (It will be up-side-down.)  This is a reflecting transformation
(d)   This function will be 5 times "steeper" and flipped up-side-down. This is both a lateral translation and a reflecting translation
(e)   This will compress the function horizontally.  This is a stretching transformation
(f)   This function is made 5 times "steeper" and is translated 3 units down. This is both a stretching and a vertical transformation. 

1.3, Problem #10.
Graph  not by plotting points, but by starting with the graph of one of the standard functions given in Section 1.2.
 

Think of the function as:  The Addition form will make it more obvious what seperate transformations are taking place.
and  are the two component parts. Break the function into its two parts to see what role each part plays
is the cosine function with a reflecting transformation (up-side-down) Sketch an up-side-down cosine curve.
Sketch the horizontal curve  on the same sketch that your up-side-down cosine curve is on. added to any curve will have the effect of raising the curve 2 units. This is a translation.
Combine the two sketches by drawing the "sum curve". Using Maple, you would use the following commands:
> with(plots);
> plot([2,-cos(x),2-cos(x)],x=-6..20);

The red curve is the graph of , the green graph is the , and the yellow curve is the , our solution.

1.3, Problem #38.
Given that  and , find the functions: (a) ,(b) ,(c) , and (d)  and their domains.
 

(a)   means:  , so we are to substitute the g function wherever the x appears in the f function. This gives us: . This simplifies to: , so . The domain of a composite function is the intersection of the domains of the functions being composed. Since , and , then the domain of  is the intersection of the two above domains. Therefore the domain of  is .
(b)   means: , so we are to substitute the f function wherever the x appears in the g function. This gives us: . This simplifies to: , so . Note that . The domain of a composite function is the intersection of the domains of the functions being composed. Since , and , then the domain of  is the intersection of the two above domains. Therefore the domain of  is .
(c)   means: , so we are to substitute the f function wherever the x appears in the f function. This gives us: . This simplifies to: , so . Since we are composing this function with itself, its domain is simply the domain of the function. There fore the domain of  is .
(d)   means: , so we are to substitute the g function wherever the x appears in the g function. This gives us: . This simplifies to: , so  Since we are composing this function with itself, its domain is simply the domain of the function. There fore the domain of  is all real numbers.


Assignment
1-47, Odds
Lesson 1.3, Pages 46-49

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