# functions

#### eddy2017

##### Full Member
Hi, the function h=24d + 4 represents the height (h) in inches of a plant after a certain number of days'(d) growth. Which of the following represents the height of the plant for the first two days?

d 0 1 2
h 4 6 8

I need a hint because i do not have the slightest idea. Thanks for your help.
eddy
I added the picture of the graph I was given,

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#### lev888

##### Senior Member
The given function converts days into inches. Plug in days (d), get height in inches (h).
The drawing does not make any sense to me.

#### JeffM

##### Elite Member
The question is not clear. The definition of the function is clear. AFTER d days, the height of the plant is h inches according to the rule h = 24d + 4.

The variable d is an independent variable of the function. An independent variable can take on any relevant value. The variable h is the dependent variable. Its value is completely and unambiguously determined by whatever values are assigned to the independent variable or independent variables. Frequently a function is defined by a formula as it is here.

As lev says, once you are given a value for an independent variable in a formula (if there is only one independent variable), you have an arithmetic problem. Just do it.

If d = 1, the formula says h = 24 * 1 + 4 = 28.

Now what exactly are the words of the problem, and was that the only box shown?

#### eddy2017

##### Full Member
The question is not clear. The definition of the function is clear. AFTER d days, the height of the plant is h inches according to the rule h = 24d + 4.

The variable d is an independent variable of the function. An independent variable can take on any relevant value. The variable h is the dependent variable. Its value is completely and unambiguously determined by whatever values are assigned to the independent variable or independent variables. Frequently a function is defined by a formula as it is here.

As lev says, once you are given a value for an independent variable in a formula (if there is only one independent variable), you have an arithmetic problem. Just do it.

If d = 1, the formula says h = 24 * 1 + 4 = 28.

Now what exactly are the words of the problem, and was that the only box shown?
Thanks to you both.
Yes, that is the only box. There should be other boxes i think. They are missing. I'm sorry.

This is the wording:
h=24d + 4 represents the height (h) in inches of a plant after a certain number of days'(d) growth. Which of the following represents the height of the plant for the first two days?
And I made a mistake. I chose that box out of the boxes given. My question should have been: is this the correct box.
According to your explanation think it is right cos plugging in the info given in the box for d it checks out.
But thanks a lot because I got the intent of the problem.

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#### eddy2017

##### Full Member
Thanks to you both.
Yes, that is the only box. There should be other boxes i think. They are missing. I'm sorry.

This is the wording:
h=24d + 4 represents the height (h) in inches of a plant after a certain number of days'(d) growth. Which of the following represents the height of the plant for the first two days?
And I made a mistake. I chose that box out of the boxes given. My question should have been: is this the correct box.
According to your explanation think it is right cos plugging in the info given in the box for d it checks out.
But thanks a lot because I got the intent of the problem.
So in day 0 height was 4.
Because if I plug 0 for d in the equation given I get 4
And when I plug 1for d I get 6 for a height
And when I plug in 2 for d I get 8 for height.
I got it.

#### Subhotosh Khan

##### Super Moderator
Staff member
Hi, the function h=24d + 4 represents the height (h) in inches of a plant after a certain number of days'(d) growth. Which of the following represents the height of the plant for the first two days?

d 0 1 2
h 4 6 8

I need a hint because i do not have the slightest idea. Thanks for your help.
eddy
I added the picture of the graph I was given,
According to the given chart, the function 'could' be:

h = 2 * d + 4

#### eddy2017

##### Full Member
Exac
According to the given chart, the function 'could' be:

h = 2 * d + 4
Exactly right, sir.

#### Subhotosh Khan

##### Super Moderator
Staff member
Exac
Exactly right, sir.
So which is the "given function"

h = 24 * d + 4..................................................as written in the OP, or

h = 2 * d + 4 ...................................................as implied by the "data provided"

#### eddy2017

##### Full Member
I am given the function to match with the data provided. The table that best matches the function is the one I drew. I totally understood now. It was just a question of substituting data given in the table for the variables in the equation.

#### Subhotosh Khan

##### Super Moderator
Staff member
I am given the function to match with the data provided. The table that best matches the function is the one I drew. I totally understood now. It was just a question of substituting data given in the table for the variables in the equation.
Where is the other table of data (that did not match the given equation according to you)?

#### JeffM

##### Elite Member
@eddy2017

You see how you waste time our time. You first said the formula was 24d + 4. Lev said the box was irrelevant. It was irrelevant because you gave the WRONG formula.

I asked for the exact wording of the problem because the box made no sense according to the formula you gave.

Subhotosh guessed that the correct formula was 2d + 4 and asked WHICH FORMULA WAS CORRECT?

All this time was wasted because you did not give us the exact and complete wording of the problem in your original post as you are told to do in the guidelines. Nor did you ever respond to the questions the helpers asked you, again in disregard of the instructions in the guidelines. Why should we help you when you pay no attention to what you have been told to do?

#### eddy2017

##### Full Member
I'm sorry Mr JeffM. It won't happen again .

#### Subhotosh Khan

##### Super Moderator
Staff member
Where is the other table of data (that did not match the given equation according to you)?

#### eddy2017

##### Full Member
Where is the other table of data (that did not match the given equation according to you)?
It is missing from my paper. It is not there. There is only thst table and that question. I asked because I needed to understand the mechanics of how to do that. If it is any good, I understood how it works.

#### Subhotosh Khan

##### Super Moderator
Staff member
It is missing from my paper. It is not there. There is only thst table and that question. I asked because I needed to understand the mechanics of how to do that. If it is any good, I understood how it works.
I chose that box out of the boxes given.
You told us that you were given multiple boxes. And now you donot have those??

I do NOT understand what you understood!!

#### eddy2017

##### Full Member
I mixed it up with another box I had that belonged to another exercise that I was going to post after that. That's what happened, sir. A mishap. I said I am sorry.

#### Jomo

##### Elite Member
You double d and add 4 to get h. Maybe you prefer if I say that you multiply d by 2 and then add 4 to get h.

If you can say what h=2d+4 means in words then that will be helpful. Again to get h you multiply d by 2 and then add 4. d can be any number you like.