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Saturday, February 22, 2014

I/D #1: Unit N Concept 7: How do SRTs and the UC relate?

INQUIRY ACTIVITY SUMMARY

1. 30º Triangle:


 
 
The activity that we did during class shows us how this 30 degree triangle relates to the unit circle. Since this is a special right triangle, we have to label it according to the rules of Special Right Triangles. The hypotenuse is 2x, the horizontal value is x radical 3 and the vertical value is x. The hypotenuse must equal 1, so we need to divide it by 2x. This is done to all the sides. Then, the hypotenuse must be labeled r, the horizontal value x, and the vertical value y. Then, you need to draw a coordinate plane and finally find the ordered pairs. The ordered pairs are found by simplifying what you divided by 2x and then by thinking of this as a graph. The ordered pairs are (0,0) , (radical 3/2,0), and (radical 3/2, 1/2) (as shown in the picture above)
 
 
2. 45º Triangle
 
 

 
 
For the 45 degree triangle,we must first find the rules for special right tringles and label it according to that. The hypotenuse is x radical 2, the horizontal value is x, and the vertical value is also x. Everything must then be divided by x radical 2 because it was divided so that it would equal 1. When it is simplified, you will get 1/ radical 2, but you must remember to rationalize it because there cannot be a radical on the bottom of a fraction. The rationalized answer will be radical 2/2. Then, you must label the sides r, x, and y, the same was that the previous example was labeled. After, draw a coordinate plane and imagine it as if it were a graph. This is how you will get your points. The points will be (0,0), (radical2/2,0), and (radical 2/2, radical 2/2), as shown in the picture above.
 
3. 60º Triangle
 
 

 
 
 
The 60 degree triangle has the same rules that a 30 degree triangle has. So, the work is practically done for this. The only thing is to switch the x and y values. The ordered pairs would then be (0,0), (1/2,0), and (1/2,radical 3/2), as shown in the picture above.
 
4.This activity helps us derive the unit circle because we now know where the ordered pairs came from in the unit circle. The ordered pairs are achieved when you divide what you divided to get the hypotenuse to equal 1 (explained above) Also, When the coordinate plane is drawn, we can see that it is separated into the four quadrants that the unit circle has.
 
5. The trianges drawn all lie on the first quadrant. The triangles are simply reflected into all of the other quadrants and the x or y values change, depending on the quadrant.
 
30º Triangle:
 
The 30 degree triangle is reflected into all of the other quadrants. The x value becomes negative in the second quadrant. Both x and y values become negative in the third quadrant. The y value becomes negative in the fourth quadrant, as shown in the picture below. (changes are highlighted)
 
 

 
 
 
45º Triangle
 
The 45 degree triangle is reflected on all of the quadrants. The x value becomes negative in the first quadrant. The x and y values become negative in the third quadrant. The y value becomes negative in the fourth quadrant. (refer to picture below)
 
 

 
 
60º Triangle
 
The 60 degree triangle is reflected on all of the quadrants. The x value becomes negative in the first quadrant. The x and y values become negative in the third quadrant. The y value becomes negative in the fourth quadrant. (refer to picture below)
 
 

 
 
 
 
INQUIRY ACTIVITY REFLECTION
 
1. ''The coolest thing I learned from this activity was'' that the unit circle consists of special right triangles that make you not have to memorize the whole unit circle because of the patterns that it has. There is a meaning to the unit circle; it is not simply just a bunch of numbers.
 
2. "This activity will help me in this unit because" it will help me fill out the unit circle a lot faster and it will most likely increase my chances of filling out the unit circle accurately.
 
3. "Something I never realized before about special right triangles and the unit circle is" that by just knowing the first quadrant, you can fill out the others as well.
 


Monday, February 10, 2014

RWA #1: Unit M Concepts 4-6 - Conic Sections in real life (parabola)

1. Mathematical Definition of a Parabola- "The set of all points equidistant from a given point known as the focus and a given line known as the directrix." (http://www.lessonpaths.com/learn/i/unit-m-conic-section-applets/parabola-drawn-from-definition-geogebra-dynamic-worksheet)

2. Algebraically: The equation for a vertical hyperbola is (x-h)^2=4p(y-k).
                           The equation for a horizontal hyperbola is (y-k)^2=4p(x-h).
When the vertex of a parabola is at the origin,  you must see if the graph is y^2 or x^2. Then, you must put in the right value for p based on if you are given the focus or directrix. The standard form would then be (x-h)^2= or (y-k)^2=, which is the equation. In the equation, h and k represent the vertex, or center of the graph. P tells us what way the graph goes. The term that is squared tells us the direction of the parabola.

This link explains the parts that parabolas have and it shows diagrams as well for reference. It is a great reference to use while learning about parabolas.
http://www.purplemath.com/modules/parabola.htm

Graphically:
This picture shows where the parts of a parabola are when it is graphed.
(http://www.teacherschoice.com.au/images/parabola_types.gif)
                  
This picture shows what way the parabola will face according to the equation.
(http://home.windstream.net/okrebs/Ch6-35.gif)
The shape of a parabola is a U, but it has many components to go along with it. The vertex of a parabola is (h,k). It is important to rememer that x always goes with h and y anways goes with k. P is the direction and distance that the vertex is from the focus. P also determines if the graph goes up, down, left, or right, depending on whether is is x^2 or y^2 and positive or negative. The axis of symmetry cuts the parabola in half. It is also perpendicular to the directrix. The directrix is found outside the parabola. It is p units away from the vertex, just as the focus is. The distance away from the vertex to the focus can also determine how wide or narrow the parabola is. The farther the focus is from the vertex, the wider it gets. The variable that is squared in a parabola deterimines the direction.
               
3. Real World Application
This is a Parabolic Heater. A parabola is what makes this heater function. (http://content.costco.com/Images/Content/Product/284457.jpg)


            

This video explains how parabolas are used in everyday things. Here it explains how the Parabolic Heater works. (http://www.youtube.com/watch?v=fV9YuF__fM4)
 
A Parabolic Heater is an example of something that uses a parabola to work. The heat source is located at the focus. It then bounces off the back to be re-directed back to the person. It bounces off in parallel lines. "The circular shape of the heater provides more energy efficiency than other electric space heaters. The parabolic design converts nearly 80 percent of electric energy into radiant heat."

Parabola's are found everywhere. They are found in things like architecture and even nature. The shape of the parabola is what makes some things work, like the Parabolic Heater. Certain things that use parabolas to work must be constructed precisely and designed accurately in order for them to work. It is amazing how parabolas make certain things work smoothly.

4. References