What’s Your Function?

Math Blog post #2

Ana Maria Lopez

Part A

1.          http://www.worldpopulationstatistics.com/china-population-2013/

2.         A relationship is a function if there is exactly one output per input

3.          In the article, there is a relationship between years and the historic population in China. In this case since each output has only one input it is a function.

4.         In this case, the meaning of this relationship is that (X) is the year and (Y) is the number of people or the population (in million) in the specific year (x). It means that there is exactly one number of people or population per year.

5.         In this case, the function is a not linear because the rate of change is not constant at every interval.

6.         It is not linear

7.          The function is not linear because the rate of change is not constant at every interval.

Proof:

 a)     ( 1960, 667.1) and ( 1965, 715.2)

715.2 – 667.1     =  48.1    = 9.62 ( R.O.C)

1965- 1960                   5

b)     ( 1980,961.2) and (1985, 1051)

1051 – 961.2   =  89.8    = 17.96

1985 – 1980           5

This is proof that the rates of change among the intervals are not constant since between 1960 and 1965 the R.O.C is 9.62 and between 1980 and 1985 the R.O.C is 17.96

8.         This is not a mathematical model because the output values do not depend on the input values. Meaning that as the years (x) change, the output values or population (Y) does not necessarily changes. This is because as years go by, population might increase of might decrease. In summary, there is no correlation between the year (x) and the amount of people in china.

Part B

1.          A relationship is not a function when there is not exactly one output per input.

2.         The chart I found represents the Average student grades on Math Exam #1

Average Student grades on Math Exam #1
Student	A	B	C	D	E	F	G	H	I
Grades	90	88	72	90	98	81	88	96	81

3.          In this chart, students had his/her own grade but there are repeated grades amongst them. For example, Student A has a 90 as well as student D.

4.         In this case, the relationship is not a function because there is more than 1 output per input, meaning that the outputs repeat themselves among the inputs. For example, both students B and G got an 88% in his/her exam.