I do not understand this. Inside the pdf in all the resoures that my teacher give me. My teacher does not teach.

[Stouffville]

A photographer uses a light meter to measure the intensity of light from a flash bulb. The intensity for theflash bulb, I, in lux, is a function of the distance from the light, d, in metres, and can be represented by

Determine the following, to two decimal places.
i) the intensity of light 3 m from the flash bulb
ii) the average rate of change in the intensity of light for the interval
iii) the approximate instantaneous rate of change in the intensity of light at exactly 3 m from the flash bulb
b) What does the sign of your answer to part a), subpart iii), indicate about the light intensity

 

[skeeter]

your attachment, "Rational Functions Review", has no problems related to light intensity that I could see ... correct me if I'm wrong, or blind.

 

[Stouffville]

your attachment, "Rational Functions Review", has no problems related to light intensity that I could see ... correct me if I'm wrong, or blind.

I know that that why I am asking for help beacuse this is a private school that I am doing for credit in math but the teacher does not teach that all. I had to do that other work on my own with somehelp.

 

[Dr.Peterson]

A photographer uses a light meter to measure the intensity of light from a flash bulb. The intensity for theflash bulb, I, in lux, is a function of the distance from the light, d, in metres, and can be represented by
View attachment 29919
Determine the following, to two decimal places.
i) the intensity of light 3 m from the flash bulb
ii) the average rate of change in the intensity of light for the interval View attachment 29920
iii) the approximate instantaneous rate of change in the intensity of light at exactly 3 m from the flash bulb
b) What does the sign of your answer to part a), subpart iii), indicate about the light intensity

Which part(s) are you asking for help with? Please show your work on whatever you can do. (Part a i should be easy; it's just asking your to evaluate.) Then ask specific questions about the rest. You should understand the rules by now.

The problem with the pdf is that it doesn't cover all the kinds of question you need, particularly average rate of change and instantaneous rate of change. It's on a different topic altogether. Have you tried looking up those terms? (I take it you don't have a textbook or recommended online resource? There are plenty of free online textbooks you could be using, if you can match one with the content of your course.)

Your snippets are missing parts, so that I couldn't answer the questions even if I wanted to; can you just show us an image of the entire problem?

 

[Stouffville]

I think for part a I got
I(d) =10/ d^2
I(3) = 10/3^2
I(3) = 10/9 or 1.11111111111


I do not get ii)
I kow the formal for AROF is y2 -y2/x2 -x1
Also know the Formal for IRAOC is the equation where you sub a lettter for 3

B I can do

as for tha problem it is down below .

 

[Otis]

I(3) = 10/9 or 1.11111111111

Hi. You've been instructed to round decimal answers to two places.

I do not get ii)
I kow the formal for AROF is y2 -y2/x2 -x1

Yes, we also call that the slope formula (the gradient of a non-vertical line connecting two points). In other words, the average rate of change between two function outputs is exactly the same as the slope of the straight line connecting those two points on the function's graph.

There's a typo above (y₂-y₂). Also, when texting algebraic ratios, we must enclose numerators and denominators within grouping symbols when either contains more than a single number. Here is the correct slope formula:

Average Rate of Change = (y₂ - y₁) / (x₂ - x₁)

Your assignment messed up the formatted interval, in part (ii). The interval goes from 1 to 3:

1 < d < 3

Let x₁ and x₂ be the endpoints of the given interval (1 and 3, respectively). Calculate y₁ and y₂. Use the slope formula.

For part (iii), I would pick x₁ and x₂ very close to 3 (like 2.9999 and 3.0001). The shorter the interval surrounding 3, the better the approximation of instantaneous rate of change. It's sad that your teacher expects you to already know these things, at the Intermediate Algebra level.



PS: Do not round intermediate values (like x1, y1, etc) to two places. Round them to four places, and round only the final answer to two places.

[imath]\;[/imath]

 

[Stouffville]

Hi. You've been instructed to round decimal answers to two places.


Yes, we also call that the slope formula (the gradient of a non-vertical line connecting two points). There's a typo above (y2-y2). Also, when texting algebraic ratios, we must enclose numerators and denominators within grouping symbols.

Average Rate of Change = (y2 - y1) / (x2 - x1)

Your assignment messed up the interval, in part (ii).

1 < d < 3

Let x1 and x2 be 1 and 3, respectively. Calculate y1 and y2. Use the slope formula.

For part (iii), I would pick x1 and x2 very close to 3 (like 2.9999 and 3.0001).



PS: Do not round intermediate values (like x1, y1, etc) to two places. Round them to four places, and round only the final answer to two places.

for part(ii) it will AROC = (y2 -y1) / (x2-x1)
AROC = (y2-y1)/(3-1)
how do I find the y values

 

[Otis]

how do I find the y values

The function outputs are the y-values. That is, the variable name I(d) is another way of writing y. It's called "function notation". You have a very bad teacher.

y = I(d)

Previously, I'd suggested 2.9999 and 3.0001 as endpoints of an interval surrounding the value 3. You may also use 3 as the beginning endpoint. That is, let x₁ be 3 and x₂ be 3.0001.

?

 

[Stouffville]

The function outputs are the y-values. That is, the variable name I(d) is another way of writing y. It's called "function notation". You have a very bad teacher.

y = I(d)

?

Yes I do

 

[Stouffville]

Ok so for AROC I got

(y2-y1)/(x2-x1
=(10-1.11)/1-3
= 8.89/-2

 

[Otis]

(10-1.11)/1-3

\(\displaystyle \frac{10 - 1.11}{1} - 3\)

That's not what you mean, but it is what you typed.

Also, you need to round answers to two decimal places. So, round to four places in your calculations, and wait until the end to round the answer to two places. Otherwise, you'll end up with round-off error in some of your answers.

AROC = (10 - 1.1111) / (1 - 3)

Do all of the arithmetic using four decimal places, and round to two places only after the last calculation.

 

[Otis]

IRAOC is the equation where you sub a lettter for 3

Please post that formula.

 

[Stouffville]

\(\displaystyle \frac{10 - 1.11}{1} - 3\)

That's not what you mean, but it is what you typed.

Also, you need to round answers to two decimal places. So, round to four places in your calculations, and wait until the end to round the answer to two places. Otherwise, you'll end up with round-off error in some answers.

AROC = (10 - 1.1111) / (1 - 3)

Do all of the arithmetic using four decimal places, and round to two places only after the last calculation.

 

[Otis]

(10 - 1.1111)/(1-3)

8.8889/(-2)

-4.44

Agree.



Please post the formula that you were given for approximating instantaneous rate of change (IROC).

[imath]\;[/imath]

 

[Stouffville]

Please post that formula.

I was given

 

[Otis]

I was given rise/run

That is not a formula for instantaneous rate of change (IROC). That's the slope formula we'd used in part (ii). The change in y is called Rise; the change in x is called Run.

In your lesson, they show a worked example of how to use the slope formula for approximating IROC at x=1 by picking a nearby value (1.001 or 1.0001).

That method is what I'd suggested. Use 3 and 3.0001 for your x-values, and proceed as you did in part (ii).



PS: There is no need for you to create and upload images of basic math statements, like d<3 and 8.8889/(-2) and rise/run. Just type them. (We can't quote images.)

[imath]\;[/imath]

 

[Stouffville]

That is not a formula for instantaneous rate of change (IROC). That's the slope formula we'd used in part (ii). The change in y is called Rise; the change in x is called Run.

In your lesson, they show a worked example of how to use the slope formula for approximating IROC at x=1 by picking a nearby value (1.001 or 1.0001).

That method is what I'd suggested. Use 3 and 3.0001 for your x-values, and proceed as you did in part (ii).



PS: There is no need for you to create and upload images of basic math statements, like d<3 and 8.8889/(-2) and rise/run. Just type them. (We can't quote images.)

[imath]\;[/imath]

Ok, Thanks for all your help. I will try to do the rest of the worksheet on my own,