Ask your own question, for FREE!
Mathematics 8 Online
OpenStudy (katecc379):

What is the rate of change between the interval of x = 3 pi over 2 and x = 2π?

OpenStudy (katecc379):

OpenStudy (katecc379):

@TheSmartOne

OpenStudy (katecc379):

@zepdrix

OpenStudy (katecc379):

@Sila1453

OpenStudy (katecc379):

@kittiwitti1

OpenStudy (kittiwitti1):

Rate of change is basically a glorified way to say "slope" lol

OpenStudy (katecc379):

yes i know but i don't know how i would put it in terms of the answer choices if that makes sense

OpenStudy (katecc379):

like with the unit circle graph

OpenStudy (mathmale):

I'd suggest you look up the formula for "average rate of change of a function f(x) on a given interval [a,b]" Which function are you discussing? Three functions are illustrated. Is it possible that the first function, given as a table of (x,y) values, has the same graph as the 2nd function?

OpenStudy (katecc379):

i understand the rate of change just in terms of the answers they give i don't understand how to write it like that look at the answer choices

OpenStudy (katecc379):

@mathmale

OpenStudy (mathmale):

Given a function f(x) defined on a closed interval [a,b], the average rate of change of this function f(x) on this interval is ... what? ? average rate of change = ----------------------------- ?

OpenStudy (mathmale):

You'll need to know this formula for quizzes and exams, so you may as well learn it now.

OpenStudy (katecc379):

y^2-y^1/x^2-x^1 i know this are you reading my question

OpenStudy (mathmale):

Unfortunately, this is not correct. y^2 represents "the square of y" and is not called for here. Mind trying again? I'd suggest you actually look up the "average rate of change" formula.

OpenStudy (mathmale):

Given a function f(x) defined on a closed interval [a,b], the average rate of change of this function f(x) on this interval is ... what? ? average rate of change = ----------------------------- ?

OpenStudy (katecc379):

i didn't mean squared i meant like the second value of y and the 2nd value of x

OpenStudy (katecc379):

wait no

OpenStudy (katecc379):

a(x)=f(b)-f(a)/b-a

OpenStudy (mathmale):

What you have typed definitely means "squared." If you now realize that this is incorrect in this context, then would you please look up the formula for average rate of change?

OpenStudy (mathmale):

You are using "a(x)" to denote "average rate of change." But there's no "x" on the right side of your equation. Instead, write "average rate of change of f on [a,b]" as the label for your definition. average rate of change of f on [a,b] = \[\frac{ f(b)-f(a) }{ b-a }\]

OpenStudy (mathmale):

THAT is the formula I was asking you to provide.

OpenStudy (katecc379):

okay

OpenStudy (katecc379):

sorry

OpenStudy (mathmale):

Now, what is the function you're working with? In other words, what is f(x)?

OpenStudy (katecc379):

well there are three look at the attachment, this is the question Which function has the greatest rate of change on the interval from x = π to x = 3 pi over 2?

OpenStudy (mathmale):

OK, right. Then a=pi and b=3pi/2. For the first function, what is the value of f(a)? of f(b)?

OpenStudy (katecc379):

but its in a table i don't understand how to do that

OpenStudy (katecc379):

did you look at the attachment?

OpenStudy (katecc379):

OpenStudy (mathmale):

Don't worry, I have looked at your attachment several times already. Does x take on the value pi in this table? Does x take on the value 3pi/2 in this table? If so, read off the corresponding function value, f(a) or f(b), from the table.

OpenStudy (katecc379):

I'm sorry i don't get it omg this is frustrating for me lol

OpenStudy (katecc379):

f(3pi/2)-f(pi)/3pi/2-pi

OpenStudy (mathmale):

Notice that you're not given 3 different graphs; you're given only one graph. Your task is to learn how to read x and y values from various different formats: from a table from a graph from a function Look at the table; find the first x value, which is a=pi. What is the corresponding y value?

OpenStudy (katecc379):

0

OpenStudy (mathmale):

Right. So, f(a)=f(pi)=0. Now find f(b) from the table. b=3pi/2.

OpenStudy (katecc379):

-4 so the first two have the same

OpenStudy (mathmale):

Unclear what you meant. Clarify that statement, please.

OpenStudy (katecc379):

the first two functions have the same rate of change, correct?

OpenStudy (mathmale):

Yes. But you have not yet found that average rate of change. Could you do that now?

OpenStudy (katecc379):

how though like you plug in the y value?

OpenStudy (mathmale):

You don't need to. You are given a table of values. You have already found out that f(b)=-4 and f(a)=0. Please evaluate f(b)-f(a).

OpenStudy (katecc379):

-4

OpenStudy (mathmale):

Right. Now please evaluate b-a.

OpenStudy (katecc379):

isn't that still -4

OpenStudy (mathmale):

No. Please don't confuse a with f(a), nor b with f(b).

OpenStudy (mathmale):

You correctly calculated f(b)-f(a). Use the same skill to calculate b-a.

OpenStudy (mathmale):

Remember that a and b are x values, whereas f(b) and f(a) are function values.

OpenStudy (mathmale):

What is a? What is b? What is b-a?

OpenStudy (katecc379):

pi/2

OpenStudy (katecc379):

sorry math is really hard for me i promise I'm not dumb lol

OpenStudy (mathmale):

correct. Now, what is the average rate of change of the given function over the interval [pi, 3pi/2]?

OpenStudy (mathmale):

You have the correct "average rate of change" formula above, remember.

OpenStudy (katecc379):

so -4/pi/2?

OpenStudy (katecc379):

-8/pi

OpenStudy (mathmale):

I see what you are saying, but it'd be better if you presented it as -4/(pi/2). The latter result can be simplified to -8/pi, yes. very good.

OpenStudy (katecc379):

so would that be the rate of change?

OpenStudy (mathmale):

AVERAGE rate of change, not just rate of change.

OpenStudy (katecc379):

okay

OpenStudy (katecc379):

so then what about the last function?

OpenStudy (mathmale):

so now you have the ave. r. of c. for the first function. What is the ave. r. of c. for the 2nd function? Hint: compare table and graph.

OpenStudy (katecc379):

same thing

OpenStudy (katecc379):

-8/pi

OpenStudy (mathmale):

correct. Take a look at the 3rd function. What do you believe is the ave. r. of c. in this case?

OpenStudy (mathmale):

Hint: What is the value of [4(0)+2] - [4(-4)+2]?

OpenStudy (katecc379):

16

OpenStudy (mathmale):

Yes, and what is the ave. r. of c. of the 3rd function on the given interval?

OpenStudy (katecc379):

32/pi?

OpenStudy (mathmale):

Yes. very good. Any questions?

OpenStudy (katecc379):

so h(x) has the greatest avg r of c?

OpenStudy (mathmale):

yes. the first 2 are equal to 8/pi and the third is equal to 16/pi.

OpenStudy (katecc379):

can u help with one more?

OpenStudy (mathmale):

Or did we lose a negative sign in there somewhere? Double check your work. What's the next problem all about?

OpenStudy (katecc379):

im so confused is that not right

OpenStudy (katecc379):

its a similar problem i just wanna make sure I'm getting it

OpenStudy (mathmale):

Too early for you to say "I'm so confused." What average rate of change did you obtain earlier for the first 2 functions?

OpenStudy (katecc379):

-4/pi

OpenStudy (katecc379):

-8/pi oops

OpenStudy (katecc379):

ok so h(x) would still have the greatest

OpenStudy (mathmale):

So, now, you are comparing -8/pi to the ave. r. of c. of the 3rd function. Yes, h(x) has the greatest ave. r. of c. of the 3 given functions. on the given interval.

OpenStudy (katecc379):

ok, can u pls help me with another

OpenStudy (mathmale):

There's no short cut; you have to calculate the actual ave. rates of change and then compare them at the end.

OpenStudy (mathmale):

Let's see the new problem.

OpenStudy (katecc379):

OpenStudy (katecc379):

so for the numerator would it be 2?

OpenStudy (katecc379):

and then the denominator pi?

OpenStudy (katecc379):

so 2/pi

OpenStudy (mathmale):

First: what are the y-values corresponding to the given x values? What is b-a? What is f(b)-f(a)?

OpenStudy (katecc379):

3-1 for b-a?

OpenStudy (katecc379):

-pi/2 for denominator

OpenStudy (mathmale):

How'd you get that? a and b are x-values. I don't see "1" or "3" on the x-axis of the graph.

OpenStudy (katecc379):

I'm sorry i got them mixed up, 3-1 would be the f values

OpenStudy (mathmale):

a=? b=?

OpenStudy (katecc379):

a=2pi b=3pi/2

OpenStudy (katecc379):

or would it be the other way

OpenStudy (mathmale):

You tell me.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!