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Monday, October 6, 2014

Blog Post #2


Part A - Function

Online, using The Economist, I was able to find an article investigating the West’s impact on Russia’s economy. The article contained the below graph, which shows a function representing the declining value of roubles (Russia’s currency) due to the invasion of Russia by large western companies.
In this graph the vertical axis represents the value of roubles per dollar (v) and the horizontal axis represents the month in the year 2014 (m). So, this function would be written as f (v) = m if put into function notation. We can tell that this graph is in fact a function because it passes the vertical line test, and each input has exactly one output. However, this function is not a linear function. There is no constant rate of change and the graph doesn’t show us a straight line. The average rate of change would need to be a constant one for this graph to be linear. It is also not a mathematical model because the value of one rouble does not at all depend upon the month or year.
   


Part B – Not A Function

            Using the online annual report of the California Commission on Health and Safety and Workers’ Compensation (CHSWC) I was able to find the below graph, which represents the comparison between the permanent disability benefit level and the benefit value (from 1984 to 2001). That being said, this graph is basically comparing between disability benefit level and benefit value, also showing how they have changed over the years.
            In order to see whether or not this is a function, we must first recall that functions pass vertical line tests and that in a function each input has exactly one output. Here, however, the only input giving the same output each time is the first input. After the first, all the following inputs give two different outputs. This violates the rules of a function, and therefore proves that the below graph does not represent a function.


3 comments:

  1. So I can see why the Rouble has been going down for the past few months. It really correlates with the amount of craziness that has been going on with them and their government. With the way that they're going, the Rouble is going to be even more worthless....

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  2. It seems like it would be so hard to tell if graph number 1 really passes the vertical line test. All the points are so close together. I really like the second example its cool that you show it through a bar graph.

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  3. hi, emma rose!

    i really like your first example. you did a great job of explaining the article generally and mathematically. and good job of using function notation! as i've mentioned in several other blog posts, it would have been nice, however, to see calculations for ROC to confirm your explanations about linearity.

    your second example actually shows two relationships that are each separate functions, so this does not qualify as a NON function.

    prof little

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