If you've only been staring at it for hours, you need to just start thinking about it. Some sample graphs might be
(a)
http://www.wolframalpha.com/input/?i=50-%7Cx-50%7C+for+0%3C%3Dx%3C%3D100
(b)
http://www.wolframalpha.com/input/?i=x+for+0%3C%3Dx%3C%3D100
(c)
http://www.wolframalpha.com/input/?i=100-x+for+0%3C%3Dx%3C%3D100
(d)
http://www.wolframalpha.com/input/?i=y%3D100+for+0%3C%3Dx%3C%3D100
(e)
http://www.wolframalpha.com/input/?i=%7C%7C100-%7Cx-50%7C%7C-30%7C+for+0%3C%3Dx%3C%3D170
#2
(a) Annie is right - they all pass the vertical line test
(b) Agree for the same reason. At no time can the balance be two different values.
(c) sister is wrong, since money must be discrete values, and many functions are continuous. But, if you allow for continuous functions, then she is right, if you allow negative values.
we'll not get into discontinuous domains...
please help!!I've been staring at this forever!!
1. Every year, Annie makes a graph showing the amount in her bank account over time. Sketch a graph showing the amount in her bank account over time from the description given. Draw a separate graph for each description. Explain each of your graphs and why you think each is correct.
(Note: You should have 5 graphs and an explanation for each graph when you are finished.)
(a) The bank account started at $0 and then started increasing. Halfway through the year, the amount started decreasing until it reached $0.
(b) The bank account started with $0 and then increased at a constant rate over time.
(c) The bank account started with money in it and then decreased at a constant rate over time.
(d) The bank account started with money in it, and the amount stayed the same for a period of time.
(e) The bank account started with money in it. Then it increased, then it decreased, then it increased again, and then it started decreasing again.
2. Annie says all of the graphs in Problem 1 are functions.
(a) Do you agree with Annie that all of the graphs are functions? Support your answer with reasoning by explaining what you think in your own words.
(b) Annie's brother claims, “A graph of the balance in a bank account over time will always be a function.” Do you agree or disagree with him? Explain your answer with support.
(c) Annie's sister says to her brother, “I think you got it backwards. I think you meant to say that any function could represent the amount of money in a bank account.” Do you think Annie's sister's statement is true or false? Explain your answer with support.
1 answer
1 answer