Math Is Fun Forum

nycguitarguy

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 566

Digital Music Revenues

The total projected worldwide digital music revenues R, in millions of dollars, for the years 2005 through 2010 can be estimated by the function

R(x) = 170.7x^2 + 1373x + 1080 where x is the number of years after 2005.

(a) Find R(0), R(3) and R(5),represents. Explain what each value represents.

(b) Find r = R(x- 5).

(c) Find r(5), r(8), and r(10), and explain what each value represents.

(d) In the model r, what does x represent?

Let me see.

Part A

I simply replace x with 0, 3, and 5 but I have no idea what each value represents.

Part B

Can you set it up for me?

Part C

I think r(5) represent the year 2005, r(8) represents the year 2008 and r(10) represents the year 2010.

You say?

Part D

I need the model r to guess what x represents.

Last edited by nycguitarguy (2024-04-23 05:44:28)

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The Rapture is the central event in biblical prophecy. The greatest truth about the Rapture is not its timing but it's reality. The Rapture will be the great disappearance.

Dr. David Jeremiah

Bob

Administrator

Registered: 2010-06-20

Posts: 10,208

Re: Digital Music Revenues

Your answers in part (a) tell us the digital revenue (how much money was made) in the years x = 0, 3 and 5 which means the years 2005, 2007, 2009.

r(x) = R(x-5) = 170.7(x-5)^2 + 1373(x-5) + 1080 

The (c) answers should be the same as the (a) answers.

In this new model when x =  5 the year is 2005, so the new model is the same as the old except the start year is now 2000.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nycguitarguy

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 566

Re: Digital Music Revenues

Your answers in part (a) tell us the digital revenue (how much money was made) in the years x = 0, 3 and 5 which means the years 2005, 2007, 2009.

r(x) = R(x-5) = 170.7(x-5)^2 + 1373(x-5) + 1080 

The (c) answers should be the same as the (a) answers.

In this new model when x =  5 the year is 2005, so the new model is the same as the old except the start year is now 2000.

Bob

I thought 0 = year 2000, 3 = year 2003 and 5 = 2005.

If not, why?

---

The Rapture is the central event in biblical prophecy. The greatest truth about the Rapture is not its timing but it's reality. The Rapture will be the great disappearance.

Dr. David Jeremiah

Bob

Administrator

Registered: 2010-06-20

Posts: 10,208

Re: Digital Music Revenues

r(x) = R(x-5) = 170.7(x-5)^2 + 1373(x-5) + 1080

If you put x = 0 that computes R(0-5) = R(-5)

However when you put x = 5 that computes R(5-5) = R(0) which is 1080 the amount for 2005.

If the formula works for years before 2005 then x=0 will compute the revenue for a year 5 years before2005, ie 2000.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nycguitarguy

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 566

Re: Digital Music Revenues

r(x) = R(x-5) = 170.7(x-5)^2 + 1373(x-5) + 1080

If you put x = 0 that computes R(0-5) = R(-5)

However when you put x = 5 that computes R(5-5) = R(0) which is 1080 the amount for 2005.

If the formula works for years before 2005 then x=0 will compute the revenue for a year 5 years before2005, ie 2000.

Bob

Ok. Thanks. I think it's time to move on.

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The Rapture is the central event in biblical prophecy. The greatest truth about the Rapture is not its timing but it's reality. The Rapture will be the great disappearance.

Dr. David Jeremiah