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Basic Math - Graphing with a Ti-83 or Ti-84 Calculator



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hello and welcome to my secret math

tutor this video we're gonna use our

ti-83 or 84 calculators and getting to

some basic graphing specifically what I

want to cover is how you can start off

entering in some sort of equation how

you can adjust your window size and

finally view that graph now also get

into some trace features or how you can

evaluate that graph once you have it on

your screen but the most important is

really how we go through these steps

then start viewing that graph itself all

right so let's go ahead and grab some

graphs and our calculators and get down

to business so the first thing we're

going to do is turn on our calculators

and get to the part of the calculator

where we need to enter in our equations

this is what we call the y equal screen

and if we're on our home screen we can

access the y equal screen by pressing

this left button here it says y equals

so let's go ahead and press that now

you'll see that it has lots of different

equations that I can type in here so

they're all labeled like y1 y2 y3 and

I'll just start off with this first one

and enter in my equation since it

already has the Y part of it in the

calculator I'm only going to enter in

this part the X cubed minus 2x part for

variables you want to use this button

right here it has an exit T of theta and

on it so let's go ahead and press and

that raise it to the power of 3 so

carrot 3 minus 2x now once I have it all

entered in looks good I'll press my

Enter button and now that equation is

stored inside the calculator yeah once I

have that done I need to actually see it

but I think it's a good idea to adjust

your window first just to make sure that

you're going to get a good picture out

of this so now that we've done the y

equals let's do the one right next to it

says window and make some adjustments

now usually by default it'll have the X

min and x max set between negative 10

and 10 and the same thing for the Y min

and the y max somewhere between negative

10 and 10 depending on what your

equation looks like you could get a

better picture by adjusting these so I'm

going to set this for negative 6 arrow

down up to 6 arrow down some more and

negative 6

six what I'm really doing here is I'm

shrinking my window size so it's really

only using X values between negative six

and six and only using Y values between

negative six and six and I'm doing that

because this graph it actually isn't too

big and I want to see all the curves

that are in it other things you may

notice in here is there is an X scale

and a Y scale that means every tick mark

you see is going to represent one so now

that we have all of that let's go ahead

and use our last button over here on the

very right that says graph we'll be able

to see what this equation actually looks

like all right sometimes it takes a few

seconds to draw it and sure enough here

we have the graph of y equals x cubed

minus 2x looks great now of course we

also want to graph another equation down

here let's go ahead and do that and

we've returned back to our y equal

screen so we can enter it as well there

we go

so my cursor is on the first equation I

don't want to mess that one up so I'm

going to press my arrow down and now

I'll do something like the square root

of x minus 20 perfect now this one if I

immediately jump to the graph screen

you're not going to be able to see it

and this is what I mean by it's a good

idea to adjust your window first that

way you have an idea of where these

things are for this one we're gonna need

a much bigger screen in order to view it

that's because it's been shifted over by

20 units so let's go into window window

I'm gonna set my X minimum I'm gonna

leave that at negative 6 why not but I'm

gonna bump up the X maximum to something

like 30 that way I can actually see

what's going on with the second graph so

now my X is somewhere between negative 6

and 30 the Y is exactly the same between

negative 6 and 6 and now let's go ahead

and see what our graph looks like now

there's that first equation it's got the

little dips and valleys in it and here's

the new one we just entered way over

here starts at x equals 20 and now I

have them both on the same screen I like

it let's go back to our y equals if you

only want to see one of these or you

want to remove one of them of course you

can hit the Clear button that will erase

one of them

you can also shut them on and off by

pressing your left arrow button until

the equal sign is highlighted then press

enter and it will essentially shut that

one off it will not graph that one and

lets us unless it's equal sign is

highlighted so now we'll go back to that

picture it only graphs the first one

doesn't even worry about the second one

nice all right let's adjust our window

just so we have that first one on there

again so that goes between negative six

and six for my window on the X&Y there's

a good picture of the first one and

let's lastly cover some tracing features

so in addition to just being able to see

this graph and know what it looks like

it's also handy to know some values on

the graph if you press the trace button

that's right next to graph it will put a

cursor on the graph that you can start

moving with your arrow buttons and find

different points on the graph so there's

that little cursor and it says that it's

approximately at x equals one point nine

and y equals three point one nine so

that's about where that is if you want

to be a little bit more precise and say

okay let's go ahead and put the cursor

at x equals one you can just use your

numerical buttons down here one and

it'll automatically know you're trying

to type in an x value so now let's press

Enter

they'll bring me to that location and it

gives me the XY pair this is that one

negative one and sure enough that's

where it's located that can be a nice

feature if you want to evaluate some

specific x values rather than just using

your arrow buttons which may or may not

skip over one as it's evaluating things

so let's give this one more try let's go

ahead and see what the value is if I

plug in a negative two we'll go ahead

and we'll type in negative two sure

enough it brings up the X automatically

even tells me near the top what I'm

evaluating this in and now I'll press

ENTER and it says that's located at the

point negative two negative four so

awfully that helps you get started with

some of the graphing features for the

graphing calculator if you'd like to see

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