help pleeease math:(?

Question

i have to find example of a funciton ( in table , graph, or equation form) from a newspaper or from internet .
i will use internet but i dont know from where should i get example of function?
can u help me please?
and after that i should know how i knew that its function
and i should find the domain and range for this graph?
i dont get it..:(

Answer 1

Go To the US Census web site to get income data
http://www.census.gov/cps/

Then look at this site to see a summary of income versus age
http://wise.fau.edu/~sfitchet/ccli/blake/age.html

The data is boiled down to:

Age
Mean Income




18 to 24 years
31,793

25 to 29 years
42,245

30 to 34 years
57,040

35 to 39 years
70,479

40 to 44 years
76,018

45 to 49 years
78,855

50 to 54 years
82,253

55 to 59 years
92,773

60 to 64 years
85,283

65 to 69 years
80,875

70 to 74 years
73,355

75 years and over
54,329

Then graph it and look for a fit
I took the mid point of the age ranges and used 78
for the last one.

It roughly looks like a parabola with an inverted vertex at
age = 57 and income = 92,773 (90000)
by translating the vertex to 57,90000
I used the equation
y=4ax^2
to solve for a

which I estimate at
-12

then create the equation that
(y-90000)=-48*(x-57)^2
or
y=(-48*(x-57)^2)+90000

you can multiply it out to get a more traditional quadratic.
Since I used Excel to help me fit the curve, I used this form.

which gives a pretty good approximatin to the curve.

It satisfies the conditions of a function since for any given x there is only one y value. The shape identifies it as a quadratic. Since the mean income has it's own statistical innacuracy, the simple parabolic estimator is actually quite elegant.

Here's my final numbers:
xAgeMean IncomeEstimated

21 18 to 24 years31,793 27792
27 25 to 29 years42,245 46800
32 30 to 34 years57,040 60000
37 35 to 39 years70,479 70800
42 40 to 44 years 76,018 79200
47 45 to 49 years 78,855 85200
52 50 to 54 years 82,253 88800
57 55 to 59 years 92,773 90000
62 60 to 64 years 85,283 88800
67 65 to 69 years 80,875 85200
72 70 to 74 years 73,355 79200
78 75 years and over 54,329 68832


j

Answer 2

A function is any graph or equation that has one out put for every input. That means that for every different number put in for the X there should be a different answer (no repeats). On graph this is shown that there are no verticle lines (no lines that are straight up and down).
Domain and range are simply to x and y values that are covered by the graph. For example the graph y=x has a domain and range of all real numbers (The graph covers all numbers) which is written like this: D (Domain):(-inf,inf) R (Range):( -inf, inf) The() indicate that the number on the end is not included. Inf stands for infinite and since inf is concept and not a number it cannot be included.

Example of a Function and its Domain and Range
Y=X D: (-inf,inf) R: (-inf, inf)
Good Luck on your Homework

Answer 3

Width times Length=area.

Answer 4

Go, no run, to the nearest Staples or other store, or go online and find the

MATH CD'S. They cover all of the grades and some are 9th through 12th....and have questions too!
So use your brain and your computer to study at home.

You can make progress on your own time, and this is what most kids who get into college are doing. Tutor using the Computer!

Answer 5

using a stock chart or a weather chart might work