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Mathematics 12 Online
Ballery1:

i can solve these questions myself but i need a proper method to do these piecewise functions.

Ballery1:

determine the value of *x*, if any, at which each function is discontinues.

Ballery1:

|dw:1568839457261:dw|

Ballery1:

@Hero

Ballery1:

we starting from basics firsts.

Hero:

Do you have any ideas on this?

Ballery1:

i can plugin some values for x and see. i do know that when x= 3, the function is zero

Hero:

But does that mean it is "discontinuous"? at x = 3?

Ballery1:

i mean i have a linear function and a point given

Ballery1:

no

Hero:

In order for the function to be discontinuous, there must be at least one value x for which f(x) is undefined.

Ballery1:

AAh icy

Ballery1:

i guess no ?

Hero:

Correct, there is no value of x for which f(x) is undefined.

Hero:

That's what discontinuous means. Discontinous function means that f(x) is "interrupted" at some point between \((-\infty, \infty)\)

Ballery1:

because i can plugin infinite x values for the first function. and same goes for the second point as well...it'll make a weird horizontal line

Hero:

Correct. No matter what x value you put into f(x), it will always generate an output value.

Ballery1:

so how do i show my work tho?

Ballery1:

i literally dont have any examples to copy off this question from

Hero:

Basically, here's what you say:

Ballery1:

all it says in the back of the book is *x=0* for the answer to that question

Hero:

No, it's not true. They're trying to say the function is discontinuous at x = 0

Ballery1:

sooo what do i do then?

Hero:

But if what you wrote is correct, the function is still continuous.

Hero:

Do me a favor, can you provide a screenshot of the problem from your book or computer?

Ballery1:

let me rewrite the question...

Ballery1:

u doubt me bro?

Hero:

No, I just want to see how the book wrote it

Ballery1:

ok one second plz

Hero:

Ah okay, sorry I completely botched this question.

Hero:

The correct answer is x = 0

Hero:

To determine if a function is discontinuous, you have to apply the "Pencil rule"

Hero:

You start from the left and then trace over the function with a pencil. The moment you have to pick the pencil up to start again with the next interval is where the function is discontinous. And that is at x = 0

Ballery1:

Hero:

So I practically gave you the write-up to this one in my previous two comments.

Ballery1:

https://www.desmos.com/calculator

Ballery1:

i've never done the pencil rule before. :/

Hero:

You can't just post the link for desmos because it has to be a unique link in order to display the graph.

Hero:

The pencil rule is not difficult. You apply it exactly as I have described.

Hero:

But let me post the graph

Hero:

The way I have graphed it is the correct graph

Hero:

Maybe you'll understand better now.

Ballery1:

AAAAAAAAAA icy now

Hero:

Geogebra is better than Desmos anyways

Ballery1:

bro, how do i show my solution algebraically tho?

Hero:

You can't show it algebraically. You can describe it as I did above though.

Ballery1:

but can i do this tho?? wait

Hero:

You can't show "lifting up a pencil" unless you post a video of yourself drawing it and then lifting up the pencil

Hero:

But you can graph it by hand and show that it is discontinuous that way.

Ballery1:

|dw:1568842231127:dw|

Hero:

Well, even if you did it this way, each point is discontinuous from the other point. You'd have to plot the points in between the points infinitely which is not possible.

Hero:

There is no practical algebraic solution. The best way to describe what is happening is using sentences to describe the pencil method.

Ballery1:

k i'll just verbally explain the method and use each equation to plot the points to show a proof

Ballery1:

thanks bro

Hero:

There's one other thing you can do though.

Ballery1:

vat?

Hero:

But it still involves showing graphically.

Ballery1:

thats k

Ballery1:

i'm willing to draw the graph

Ballery1:

ight thanks mate.

Ballery1:

wow do u have a premium account with study.com?

Ballery1:

i need to make notes for calc 1 and linear alg

Ballery1:

it tells me to register to view the whole video

Hero:

Ah I see. I didn't realize it.

Ballery1:

do u have a subscription to a math site?

Ballery1:

i could use some help :/

Hero:

I could have sworn I gave you ixl

Ballery1:

bro i never really used it cuz i changed my mind on this program like 90 times

Hero:

What program?

Ballery1:

network eng

Hero:

Oh you're still doing that

Ballery1:

bruhh i haven't even started

Hero:

I bet

Hero:

You should do something you're actually interested in that you can actually finish.

Ballery1:

im scared, i know i can do it but i'm afraid at the same time

Hero:

Just pretend you're chinese.

Hero:

They finish everything faster than we do and fear nothing.

Ballery1:

i like networking. i think it's amazing...it's just the maths and physics that's getting in my way

Hero:

Yup

Ballery1:

so yeah.. i wanna make notes for math courses fast so i can move on with other stuff

Hero:

You don't need study.com to take notes.

Hero:

Just do it with Khan Academy

Ballery1:

like coding, programming, networking ..uhg

Hero:

There's a way to get an archive of all the videos without having to do the lessons.

Ballery1:

but he does baby lotion soft questions and my textbook is diamond hard...it'll be no use for me

Hero:

Which book are you studying

Ballery1:

the one prof made for us /.-

Hero:

Damn

Ballery1:

yeah.... lol

Hero:

Those are the worst ones

Ballery1:

literally no freking solutions to questions or proper examples...i swear these teachers are so lazy

Hero:

But what is the isbn?

Hero:

Every book has an isbn

Hero:

Can't be published without it

Ballery1:

there's no isbn on this book....or at least that's what i think...the bar code is nearly erased....let me post

Hero:

You can find the isbn on the back of the title page toward the very front of the book. Like within the first 3-5 pages

Ballery1:

Ballery1:

Ballery1:

Ballery1:

Hero:

Wow I've never seen that before.

Hero:

It's not published properly. Has a copyright but no ISBN

Ballery1:

Hero:

Yep, good luck.

Ballery1:

bro, send me the website thingy

Hero:

You should drop out and find a school where you can have access to better resources to help you. That school is trying to limit you with all kinds of restrictions. Might as well be a prison

Hero:

I can find a link to khan academy's videos but it will take some time.

Ballery1:

bro :/

Hero:

What do you want?

Ballery1:

can i have link to the math site you use with subscription plz : )

Ballery1:

plz plz plz plz

Ballery1:

i lost the link u gave me :/

Hero:

But don't sleep on Khan Academy. It's the general concepts that he is great with explaining.

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