Blog Post 2: What's Your Function: Aroob Qutub

Part A:

-http://www.tradingeconomics.com/united-states/gdp-growth

-A vertical line test could be done to determine wether a relationship is a function, and also a relationship must have one output for each input.

Graph of GDP growth rate in the United States from 2012-2015

- This graph represents the growth rate of The Gross Domestic Product (GDP) in the United States from 2012 to 2015.

-This graph is proved to be a function, because each input is paired with one output, so each year shows a different growth rate. This relation passes the Vertical line test, because there are no vertical lines that intersect the graph at more than one point.

-The relation has both dependent variables the (year) and (GDP growth rate), and the average rate of change between the years isn't constant and the graph isn't a straight line, therefore this relation does not account to be a linear function.

-The function can not be a mathematical model because the (GDP growth rate) depends on economic activity and not on the (year).

http://www.tradingeconomics.com/united-states/gdp-growth

Part B:

-relationships that have more than one output for each input can not be functions. 

-http://www.economist.com/news/economic-and-financial-indicators/21641244-metal-prices

-This graph shows the rate of fall in different metal prices in China from 2011-2015. The prices of different metals such as zinc, aluminum, nickel, and iron each decrease at a different percentage each year starting from 2011 to 2015, but all have a different rate of change that is not constant throughout the years.

- This relationship does not represent a function because the rates of price decrease in the graph overlap, which means that one input has more than one output.

http://www.economist.com/news/economic-and-financial-indicators/21641244-metal-prices