#precalculus

1 messages · Page 305 of 1

lavish edge
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yes

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its given in the fig

vapid plaza
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Well (x,0) doesn’t always lie on the circle. (r,0) does

lavish edge
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no noo

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i know that cos0 is 1 and sin 0 is 0

vapid plaza
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But in the special case where x = r,
(x,0) is (r,0) and therefore lies on the circle.

lavish edge
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ok but

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look look

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in the figure

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the terminal side

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as in figure

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theta is given as theta say 30

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alright

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so how can you have theta = 0 for x in the same figure

vapid plaza
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Theta is 30 in the figure, but the figure represents one only possible point on the circle.

lavish edge
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so if theta is given as 0

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30

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can we use the same variable theta for 0

vapid plaza
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The figure only shows what happens when theta = 30!!!
when theta = 0, we would get a different figure

lavish edge
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NO i am not saying that

full pagoda
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i have not the slightest clue what you're trying to ask

vapid plaza
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Bruh

lavish edge
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just look at the initial side x. If you see its coordinates youll get x,0 which is the same as xcos theta and xsin theta when theta is 0 but in the figure theta is already defined and is a positive angle

vapid plaza
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Yeh but in the figure (x,0) is not on the circle we were talking about anyways!!!

lavish edge
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so how cn we take theta as 0 for x and theta = some positive angle for another side

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if theta is already mentioned to be some value can like 30 for one question can we take theta as some other value for the SAME question?

vapid plaza
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What question?

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Wdym question??

lavish edge
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A question?

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a sentence worded or expressed so as to elicit information.

vapid plaza
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There was a question? You never mentioned there was a question.

lavish edge
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look at the figure

vapid plaza
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There is no “question” in the figure.

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The question is because you’re confused

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💀

lavish edge
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yeah i am

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thats why im asking

vapid plaza
lavish edge
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does x form a 0 degree angle

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with the base

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or not

vapid plaza
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Yeh so what?

lavish edge
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whatever im talking about is from the figure

vapid plaza
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In the figure, “x form a 0 degree angle with the base”

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But why is that a problem?

lavish edge
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its not

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if it does form 0 degrees with the base

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does that mean theta is the theta in the figure or 0

full pagoda
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theta is an arbitrary angle measurement

vapid plaza
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The figure is trying to show that (x,y) lies on the circle.
So of course it would display theta as the corresponding theta for (x,y)

lavish edge
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and for x,0 whats the corresponding theta

vapid plaza
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0

lavish edge
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so therer 2 thetas right

hushed sphinx
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If theta=0 then there isn't really any triangle, just a single line from the origin out to (1,0).

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There are infinitely many possible thetas.

vapid plaza
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Besides, (x,0) doesn’t lie on the circle, (r,0) does

lavish edge
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yes

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but (r,0) is the same as rcos0 and rsin0

vapid plaza
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Yes

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So r lies on the circle

lavish edge
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does that mean theta is 0

vapid plaza
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Theta is not just “some value” for an entire circle

hushed sphinx
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Yes, theta is whatever you give as input to the trig functions.

lavish edge
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look what im trying to say is some point is given P(x,y) with some theta as the focus. If somehow theta is 30 we will get x as root 3/2 and y as 1/2 for a unit circle. Theta is defined to be 30. But if the side x lies on the circle for the SAME example, it will still have the points r,0 which is the same as rcos theta and r sin theta. Now if theta is defined as 30 degrees how come we still get r,0 which occurs when theta is 0

hushed sphinx
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Theta is defined to be 30.
No it isn't.

full pagoda
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you just said theta is two different angles

vapid plaza
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There is no problem!!!!! If theta is 30, we get a point that lies on the circle, if theta is 0, we get another point that lies on the circle.

hushed sphinx
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Just because you can choose to let theta be 30 doesn't mean theta must always be set to 30.

lavish edge
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im not saying theta is 30 and 0

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if theta is 30

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we will still get the base as r,0

full pagoda
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"the base"?

lavish edge
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yes

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initial side

full pagoda
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if theta is 30, you're not looking at the coordinates of the initial side

vapid plaza
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Hmm Vedanth what are your hobbies? catGiggle

lavish edge
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physics and maths studies

vapid plaza
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Anything else?

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I was trying to say do sth else then return to this “problem”.

lavish edge
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No

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i understand everything you guys are saying

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but it doesnt answer my question cause i dont know how to explain my question in text

vapid plaza
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:/

hushed sphinx
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It still falsely claims, "theta is defined to be 30".

lavish edge
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theta is defined to be 30

hushed sphinx
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No it is not.

lavish edge
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as per question

full pagoda
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what question???

lavish edge
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a sentence worded or expressed so as to elicit information.

hushed sphinx
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The question you still haven't shown us?

lavish edge
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theres no question

full pagoda
hushed sphinx
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Please post a picture of the text that defines theta to be 30.

vapid plaza
lavish edge
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i created a scendario where theta is 30

hushed sphinx
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The damn thing claims that theta is defined to be 30, which is not true, It is false. it is not the case.

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It is not even an EX-fact.

lavish edge
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If somehow theta is 30 we will get x as root 3/2 and y as 1/2 for a unit circle. Theta is defined to be 30.

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first i said if somehow theta is 30

full pagoda
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bro

lavish edge
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then i claimed theta is 30

lavish edge
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me

hushed sphinx
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No, theta is not defined to be 30, no matter how often you repeat that false claim.

full pagoda
lavish edge
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ok

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theta is defined to be 30 as per question

full pagoda
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lol

hushed sphinx
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You repeat your false claim again. That does not make it more true this time either.

lavish edge
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its true

hushed sphinx
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You lie.

lavish edge
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truth is relative

hushed sphinx
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It there was a definition of theta as 30, it would have been a simple matter for you to post a scan, photo, or screenshot of that definition.

lavish edge
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did i ever say

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theta us defined to be 30

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is

full pagoda
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yes

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like 40 times

lavish edge
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no lemme finish

hushed sphinx
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You have not provided that. I confidently conclude that you have not in fact seen such a definition in whatever it is you're quoting from.

lavish edge
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did i ever say theta is defined to be 30 for every scenario

hushed sphinx
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You keep saying that theta is definied to be 30 in the thing you're talking about.

lavish edge
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yes

hushed sphinx
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From which you have still not shown the definition you keep claiming exists.

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Come on. Pics or it didn't happen.

vapid plaza
lavish edge
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no

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is theta 30 or 0

hushed sphinx
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You keep claiming that you have a definition that says it is 30.

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If it is 30, it is not 0.

lavish edge
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no

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just listen to me

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if we have an example

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where it says theta is 30 degrees

vapid plaza
hushed sphinx
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Please show the place where it says so.

lavish edge
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thanks for the great help

hushed sphinx
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The figure looks like a fair bit less than 30, but never mind. The author might have intended it to be 30 when they wrote the definition that Vedanth refuses to show.

lavish edge
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its from a google image

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i-

vapid plaza
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Go do something else jesse jesse

lavish edge
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can a question have two different thetas'

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These are the most important rules. For more info see info.

If you see anyone violating these, feel free to ping <@&268886789983436800>.

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mniip — 06/05/2021
(Revision as of June 4, 2021)

slender river
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oops

lavish edge
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<@&268886789983436800>

slender river
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you accidentally pinged us

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or

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twice

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what

stuck lark
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???

lavish edge
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yes

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Respect that other people might be at a different stage in their education than you, what is obvious to you might not be obvious to them.

full pagoda
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if you are looking at the set of coordinates that lie on the unit circle when theta = 30 degrees, you are not simultaneously looking at a different set of coordinates that relates to a different theta

full pagoda
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we've told you time and time again that what you're saying makes zero sense yet you keep saying it over and over again and expecting things to change

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definition of insanity

lavish edge
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Be rational and exercise critical thinking. If someone makes a mistake in their reasoning, politely point it out.

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can a question have two thetas

full pagoda
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entirely depends on the context of the question...

short sorrel
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i dont see anyone being rude or untoward

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youre asking a vague question thats hard to interpret with imprecise wording and unclear intent/clarification

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people are asking you for an explanation

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you are being dodgy

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almost makes me think this is for a test or something

hushed sphinx
short sorrel
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i was responding to the mod pings

dapper brook
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How come I’m learning trig while I’m in pre-cal

hushed sphinx
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Why wouldn't you? It's pretty common to teach trigonometry before calculus.

viscid thistle
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ik this is a lot to ask but could someone plz offer a step by step by step explanation for how each step works. I’m very lost here; the only step I understand is get is when we distribute the square of the absolute value of the difference of Ba_i and Cb_i

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the book I’m using rn is skimming complex numbers and assumes the reader already knows about em ;/

low slate
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Bit of a multi step problem, but i dont really understand how to find the answer and if someone can help me out it would be appreciated

full pagoda
fast monolith
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I don't know what the first step is, if possible, can someone explain how to solve this?

full pagoda
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try getting everything in terms of sin and cos

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see what you can do from there

low slate
full pagoda
low slate
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correct

full pagoda
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so where the ladder touches the ground

low slate
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so the angle on the top would be 15

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right?

full pagoda
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i mean yeah but that's not needed

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well i guess

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you could

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but

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lol

low slate
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and the hypotunese is 24

full pagoda
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right

low slate
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but then how do u go from there

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cuz i only have angles and a side

full pagoda
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can i see the diagram you've drawn?

low slate
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yea sure gimme 1 sec

full pagoda
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you can set up a trig ratio with a missing variable using a right triangle, an angle, and a side

low slate
full pagoda
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looks good

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so using that, you need to find both other sides

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you can use two different trig functions to set up an equation for either side

low slate
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ok

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how to i figure out the trig functions tho

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thats the main part im confused on

full pagoda
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well what ratio does sin represent?

lofty yarrow
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⠘⣿⣿⣿⣿⣿⣿⣿⣿⡆⠄⠄⠄⠄⠄⠄⠄⠄⠹⠈⢋⣽⣿⣿⣿⣿⣵⣾⠃⠄
⠄⠘⣿⣿⣿⣿⣿⣿⣿⣿⠄⣴⣿⣶⣄⠄⣴⣶⠄⢀⣾⣿⣿⣿⣿⣿⣿⠃⠄⠄
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⠄⠄⠄⠄⠄⠄⠄⠉⠻⣿⣿⣾⣦⡙⠻⣷⣾⣿⠃⠿⠋⠁⠄⠄⠄⠄⠄⢀⣠⣴
⣿⣿⣿⣶⣶⣮⣥⣒⠲⢮⣝⡿⣿⣿⡆⣿⡿⠃⠄⠄⠄⠄⠄⠄⠄⣠⣴⣿⣿⣿

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niceeee

viscid thistle
viscid thistle
#

Let me know if you want something explained in more detail

viscid thistle
# viscid thistle ik this is a lot to ask but could someone plz offer a step by step by step expla...

https://math.stackexchange.com/questions/446148/cauchy-schwarz-for-complex-numbers
also you can prove a stronger version of this with cauchy-schwarz

low slate
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do u have to use sin ?

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like how do u know which one to use

full pagoda
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depends on which sides you have relative to your angle

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in your triangle, you have an angle and the hypotenuse

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and you're looking for both sides, so to find the first side, you can use either sin or cos

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since both utilize the hypotenuse that you know, the angle that you know, and an unknown side

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so one equation, one variable

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solvable

sick steppe
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🤨

vivid void
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@viscid thistle could you like

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not post this in 3 channels

viscid thistle
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for calculus questions dm

mellow tapir
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hey guys my friend has this question and i don't know how to solve it either so can someone help us

hushed sphinx
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Hmm, there are five "I don't know yet"s and 96 is 3·2^5.

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That indicates there's probably a progression where each successive declaration of ignorance doubles the numbers.

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The guess that would fit best with that hypothesis would be ||oops, I see it's a still open contest||.

mellow tapir
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nah the contest is over but that was a cool observation

tribal lodge
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Can someone help explain something

mellow tapir
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yeah i can help

tribal lodge
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Can you vc???

mellow tapir
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nah

tribal lodge
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🥲

hushed sphinx
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If you state what it is you need explained, perhaps someone who knows will reply.

tribal lodge
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I’m slow that’s why I need to be in a vc

viscid thistle
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i am not sure how to find the real zeroes

hushed sphinx
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Numerically.

viscid thistle
hushed sphinx
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Basically systematic trial and error until you know a short enough interval where the function changes sign that it approximates the root well enough for your purposes.

cerulean flower
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hey guys, when theres a slant asymptote of a rational function, how do you know when and where it gets crossed by the function?

jolly raven
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i dont think functions can cross slant asymptotes but i might be wrong

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if they were to be passed, it would probably be in a central part of the function bounded by vertical asymptotes where the function is not continuous all the way to both infinities

cerulean flower
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i know that slant asymptotes can be crossed, and you are right

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but i wanted to know how to find the exact point

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of where the function crosses the slant asymp

hushed sphinx
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An example of a crossing would be f(x) = x - x/(1+x²)

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I don't think there's a particular procedure for that, though. Subtract the equation for the asymptote, and look for roots of the numerator of the resulting rational function, is the best general thing you can do.

cerulean flower
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i know that for finding the slant asymptote, you have to divide the numerator and the denominator, and whatever remainder you get determines if and where it crosses the slant asymp

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wait a second

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i answered my own question

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thanks for clearing some things up guys

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so if anyone wants to know ig, if the remainder you get when dividing the num and denom of a rational function is a constant, then the slant asymptote doesnt get crossed. if it has a variable (ex: 2x-1), then solve for the variable (x=1/2) and plug the answer into the og rational function to get the y value of the coordinate. (not so sure ab the last part but its what i remember)

grave tartan
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I have to do this without calc, how would i go about doing this

willow bear
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you can construct a piecewise-linear function that does this

grave tartan
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see that came to mind

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except we havent covered piece wise

willow bear
grave tartan
willow bear
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no calc and no piecewise functions...

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i mean like

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you COULD do it all exclusively with absolute values i guess

grave tartan
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im like stumped

willow bear
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at least tell me you have access to that

grave tartan
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wouldn't it also be piecewise tho

willow bear
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the piecewiseness would be hidden

grave tartan
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no we do I just don't know how to combine like

willow bear
#

you said "we haven't covered piecewise functions"

grave tartan
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absolute values with different vertexes

viscid thistle
willow bear
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a polynomial would require calculus to properly construct

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and we are told we aren't allowed calculus

grave tartan
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^^

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I tried using like different bell curve shaped graphs but they don't work nice

viscid thistle
willow bear
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you'd need the polynomial to have at least degree 4

grave tartan
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which means 5 unknown variables

grave tartan
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so its not nice

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unless I just give myself like (0,0) and (5, 5)

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but its a cancerous system of equations

willow bear
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this ban on piecewise functions is super annoying ngl

grave tartan
#

IKKK

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i am just going to assume the worksheet was meant for after and she either assigned it too early or changed the flow of the curriculum this year

viscid thistle
# grave tartan

wait, how many degrees a function with 3 relative maximums has?

grave tartan
#

but either way wanted piece wise

grave tartan
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yeah 4

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but I think I am allowed to have more

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just has to have a minimum degree of 4

willow bear
viscid thistle
# willow bear

this way of solving ignores the fact that the maximums are on the line y = x

viscid thistle
# willow bear

the author of the problem wouldnt give the three maximums on y =x for no reason

grave tartan
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true but at this point I don't want the ingenius solution

grave tartan
willow bear
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if necessary

vivid void
viscid thistle
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idk if this is possible

vivid void
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you know what

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a sine function would actually work

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you just need a period of 1

viscid thistle
vivid void
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i’m aware

viscid thistle
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sine functions dont go above 1

vivid void
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that’s why you give it a variable coefficient

willow bear
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doing that will screw up the location of the maximum points

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and pinning those down will take calculus

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so that is a no go

grave tartan
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tried that too

viscid thistle
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something like this

viscid thistle
grave tartan
#

fortunately $f\left(x\right)=-2.5\left|x\right|-1.5\left|x-1\right|+3\left|x-1.5\right|-4\left|x-2\right|+5\left|x-2.5\right|-6\left|x-3\right|+10.5$ is

obsidian monolithBOT
grave tartan
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was also thinking about it

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would x^2 - x*ceil(x-1) work

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do you need points on either side to be considered a max

peak moss
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Sorry to interrupt, but I'm stuck with this question. I've tried to factor the (sin2x•cos2x)² • cos 2x, but the answer that I got is too different compared to the scheme. I'm a bit stuck, and in need of help 🤲🏻

opaque idol
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sub sin^2(2x) = 1- cos^2(2x)?

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then let u = 2x or something?

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or u = sin 2x

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idk

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try it and see if it works

peak moss
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I’ll try in a bit

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Thenk youuue

vivid void
#

precalculus

viscid thistle
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wdym quantum that looks like precalc to me

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antiderivatives are like algebra or somthin

vivid void
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ok let me just post a nonhomogeneous ode here then

vapid plaza
viscid thistle
willow bear
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oh yeah you're right

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you need two minimum points between the maxima

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so that's 5 turning points

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...why degree 7 tho

viscid thistle
# grave tartan

so i know this wasn't what the question was asking but you can find the minimum polynomial that satisfies this with some calc

willow bear
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it is impossible to do it with 6?

viscid thistle
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yeah it is impossible with 6

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i worked it out

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,rotate

obsidian monolithBOT
viscid thistle
#

,rotate

obsidian monolithBOT
viscid thistle
#

original problem seems impossible without using either piecewise functions or calculus

viscid thistle
#

everything else still checks out though

viscid thistle
peak creek
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Hello

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Why does "Out of these, only x=1 is within the interval (0,3)"?

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The mean value theoreme does not apply to the limit of the interval?

willow bear
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the mean value theorem asserts the existence of a point in the open interval (a,b)

gloomy gulch
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I need to create a function with all these requirements. Cannot to it. Need help please

vivid void
#

it would help to write it as this

#

$\frac{f(5)-f(1)}{5-1} =5,\ \frac{f(10)-f(1)}{10-1} =-20 \ \frac{f(9)-f(2)}{9-2} =0,\ f’(2) = -10,\ f’(3) = 0$

obsidian monolithBOT
#

quantum

vivid void
#

notice what the third one implies

#

i would assume that this is a uh

#

maybe third degree polynomial

#

not sure honestly

#

actually no

#

assume it’s in the form of ax^2+bx+c

#

since you would have three equations in three variables and two equations in two variables then

#

@gloomy gulch

#

this is just a system of equations in disguise

#

seems kinda fun honestly

gloomy gulch
#

@vivid void Hey. I just came sorry

vivid void
#

it’s fine

#

i didn’t expect you to respond immediately

gloomy gulch
#

Lol. I’m trying to solve this that’s why I came in quickly

vivid void
#

yeah considering that you have the two derivatives this shouldn’t take too long

gloomy gulch
#

Well, it is to me 😂

#

The thing is, I was able to make a function that meats the first requirement

#

But then, when I try to meet the second, my first requirement is lost

#

I’m doing trial and error

vivid void
#

you shouldn’t do that

vivid void
gloomy gulch
#

That actually made things easier now that I know how my function would look

gloomy gulch
#

Nvm

#

I have two functions. One that matches the first requirement and one that matches the second. Maybe I should combine them?

vivid void
#

note that this guess of it being a quadratic could be wrong

#

if it is wrong we can try something else so it’s fine

gloomy gulch
#

Hmmm this is weird

vivid void
#

$f(5)-f(1) = 20 \ f(10)-f(1) = -180 \ f(9)-f(2) = 0 \ f’(2) = -10 \ f’(3) = 0$

obsidian monolithBOT
#

quantum

gloomy gulch
#

Nvm nvm. Those numbers are supposed to be my numerators?

#

For example, the first requirement. My denominator is 4 so we need 20 in the numerator so when we divide, we get 5 which is the rate of change

#

Idk I’m confused

vivid void
#

yeah i just multiplied both sides by the denominator

gloomy gulch
#

Ok that helps

gloomy gulch
#

Well if I spend 20 hours straight of trial and error I would be able to get it lol but that’s not the efficient way

#

Hopefully we don’t need to include cos, and sin in the function

vivid void
#

@gloomy gulch i’ll just write it out and see if my guess is wrong

vivid void
#

$25a+5b+c-(a+b+c) = 20 \ 100a+10b+c-(a+b+c) = -180 \ 81a+9b+c-(4a+2b+c) = 0 \ 4a+b = -10 \ 6a+b = 0$

obsidian monolithBOT
#

quantum

vivid void
#

$-4a-b = 10 \ 6a+b = 0$

obsidian monolithBOT
#

quantum

vivid void
#

@gloomy gulch this might actually be a quartic lol

#

or something

gloomy gulch
#

Lol please no

vivid void
#

maybe even a quintic

#

remember that it’s really just a big system

#

$24a+4b = 20 \ 99a+9b = -180 \ 77a+7b = 0 \ 4a+b = -10 \ 6a+b = 0$

obsidian monolithBOT
#

quantum

vivid void
#

this is what i get after simplifying

#

i actually got a = 5, b = -30 for this

#

but i’m pretty sure that’s wrong

#

yeah that’s definitely wrong

#

this would be a uh

#

hmm

#

quintic yeah

#

i am not writing all that out on latex lol

#

a quintic has 5 coefficients excluding the constant at the end

#

and notice that none of these have that constant term

gloomy gulch
#

Hmmmm

vivid void
#

i’m pretty sure this if in the form of $ax^5+bx^4+cx^3+dx^2+ex+f$

obsidian monolithBOT
#

quantum

vivid void
#

so many letters i needed to recite the alphabet for the last one

#

not even a joke

gloomy gulch
#

😂

#

I think your going too far tho

vivid void
#

no i’m seriously not

#

this isn’t a joke

tight compass
#

just use a_i instead.

vivid void
#

are you triggered by me using e as a coefficient

#

i was about to say something about that lol

#

i don’t like it either

gloomy gulch
#

No no, it’s weird, but no worries

tight compass
#

Imagine you need to 26 + 1 degree polynomial.

vivid void
#

i would just not do the assignment at that point

gloomy gulch
#

I wish I can’t 😂

vivid void
#

augmented matrix time 😎

gloomy gulch
#

If I decide to surrender I’ll just create a function that meets one requirement. That’s what I’m capable of 😅

vivid void
#

well you have all you need now

#

just gotta power through i guess

gloomy gulch
#

Yup. I’ll try my best

#

Thanks anyways

vivid void
#

no problem

#

oh and if you couldn’t tell

gloomy gulch
#

I hope no one falls in this type of question 😂

vivid void
#

do the last three equations first

#

well

#

at least the last one and the third one

#

since they both equal 0

#

so you don’t have to worry about any constants there

gloomy gulch
#

Yes yes

#

Well the question is out of 4 marks. If I manage to get at least 3 (which I think I can). There’s at least 2.5/4

vivid void
#

although i’m not sure how you would get the constant term at the very end

#

hmm

mild root
#

hi, could some EXPLAIN to me how I could solve this?

#

#3

full dock
#

then

#

find the resultant vector's magnitude and direction by taking the sum of the y and x components

viscid thistle
vivid void
#

cringe

low slate
#

what does 6 1/2 represent?

#

is that the radius or the circumfrence?

hushed sphinx
#

My first guess would be diameter.

low slate
#

seems simple but i feel stuck

vivid void
#

same honestly

#

wait

#

i assume that the information given means that 108 = 2x+2y

#

so just solve for y @low slate

low slate
#

ok ill try

graceful fiber
#

y=(x^3-9x)/(x^2+2x-15) graph

#

i know that it looks like a slanted hyperbola but i cant figure out how to get the second asymptote

gloomy gulch
#

@vivid void hey, remember me from yesterday? The guy who asked for help in finding average rate of change. Well guess what? It turns out the question only asks to sketch a graph that meets those requirements and not build a function with numbers. I think that’s suppose to make it easier 😂

vivid void
#

@gloomy gulch bruh

#

did you solve it though? lol

gloomy gulch
#

I’m working on it lol

#

After yesterday I just quit

#

Good practice tho

vivid void
#

yeah if it wasn’t such a big system it would be fun

gloomy gulch
#

Graph will still have big numbers in it

#

It’ll be a sinusoidal behaviour too

#

Just a quick question, what do you recommend should my scale go by?

#

Because there will be some big numbers, I don’t want to have a graph that looks gigantic @vivid void

vivid void
#

repost the question and i’ll help in a minute

gloomy gulch
#

Just a quick question, what do you recommend should my scale go by? Because there will be some big numbers like -180, I don’t want to keep extending my graph for ever

vivid void
#

@gloomy gulch no i meant the question you sent yesterday

gloomy gulch
#

My bad

#

I’m thinking a scale of 5?

vivid void
#

yeah that’s a good idea

#

because the height will have to be at least like 90 because of the second condition

gloomy gulch
#

Yes

#

I’ve calculated and the max hight would be 200

#

😬

#

That’s a lot. My teacher would hate my graph lol

graceful fiber
#

y=(x^3-9x)/(x^2+2x-15) graph finding the asymptotes

dim lodge
#

hey can anyone help me with precalculus

willow bear
dim lodge
#

its delta math work 😭

#

ive been at this for like 4 hours now

#

but theres a penalty so if i get it wrong it makes me go back

willow bear
#

well if you don't show us the problem(s) then we can't help you now can we

dim lodge
#

alr ur making me feel like a dumbass now

#

lmfao

#

but im trynna figure out how to send pics cuz im on pc

uncut mulch
#

snapshot tool

#

win+shift+s

willow bear
#

or Prt Sc

#

should be a key on your keyboard

dim lodge
willow bear
#

okay

#

have you made any progress on this or are you stuck not knowing how to begin?

dim lodge
#

i know how to begin but its just i make some sort of mistake somewhere

#

so heres what i do

#

instad of cosx i just substitute x

#

like 4x^2 - 3 = 0

#

then sqrt 3 / 2

willow bear
#

then sqrt 3 / 2

#

then what?

#

okay first off

#

maybe you shouldn't use the same letter for two different things

#

let's call cos(x) something like t instead to avoid confusion

#

so you have the equation 4t^2 - 3 = 0

dim lodge
#

ok ok

willow bear
#

what did you do afterward?

dim lodge
#

afterwards i do cos^-1 (sqrt3/2)

willow bear
#

no

#

what did you do immediately after writing down the equation 4t^2 - 3 = 0?

dim lodge
#

oh

#

solved for t

willow bear
#

show your work in solving for t.

#

i have a suspicion you're making a mistake somewhere in that part, and i want to ensure it doesn't happen.

dim lodge
#

uhm

#

add 3

#

to 0

#

then divide by 4

#

so 3/4

#

then square root

willow bear
#

i said show not tell

dim lodge
#

ohhh

willow bear
#

do you have it written out on paper somewhere

#

it needs to be written out on paper in order to diagnose potential errors

viscid thistle
#

would this be 8x?

vivid void
#

no

#

do you know how to find an inverse function

tight compass
# viscid thistle

Forgot about using the technique for finding the inverse of f, think about what f is doing to x. It scales it by 5 then added to it by 3. So what do you think the inverse should do?

viscid thistle
tight compass
#

Yep.

viscid thistle
#

how about this?

tight compass
#

You can split it to 1 + 2/x

viscid thistle
#

ok

tight compass
#

So apply what we did above to this.

viscid thistle
#

ohh

#

okay 1 minute

#

-2 then times x?

#

so -x?

#

nope

tight compass
#

Think about what f is doing to x. Clearly we first take x to 1/x.

viscid thistle
#

im going to be honest. im really confused rn lol

#

maybe im tired but i do not understand

tight compass
#

So x-1 then (x-1)/2 then 2/(x-1), for x in the domain of inverse f. Do you see it?

#

Generally to find the inverse of f change f(x) to y to make it easier, then switch the variables y and x then solve for y.

viscid thistle
#

ok 1 second

#

need to read it all lol

#

where did you get the f from originally?

tight compass
viscid thistle
#

in a message before you said f-1 first or something similar i think

#

you edited it though so it doesnt matter

#

one minute

#

thanks for your help so far but i think ill try tomorrow.

#

its currently 3 am lol and i think im too tired to understand

tight compass
#

Wake up, read your notes and watch videos explaining it.

viscid thistle
#

@tight compass a friend explained it too me and made me understand it better

#

it was 2/x-3

tight compass
viscid thistle
#

figured out the other few questions after too lol

dawn sun
#

Hello is there someone here who could help me please?

stuck lark
limpid dune
#

Hello

desert badger
#

Anyone help

full pagoda
#

we can't see any of the information given

desert badger
full pagoda
#

,rotate -90

obsidian monolithBOT
full pagoda
#

where'd you get 56 degrees from?

desert badger
#

Idk

#

I try to solve it

full pagoda
#

how exactly did you do that

#

i say that because it's close

#

i'd like to know where you went wrong

desert badger
#

I did

#

180-29-95

full pagoda
#

where'd 95 come from?

desert badger
#

B

full pagoda
#

b is not 95

#

3 degrees more than vertical

#

what angle would represent vertical?

desert badger
#

Not sure

full pagoda
#

what is angle C in this?

desert badger
#

c

full pagoda
#

what is the value of angle C

desert badger
#

90

full pagoda
#

right

#

and that's vertical

#

straight line from the ground up

#

so what's 3 degrees more than vertical?

desert badger
#

93

full pagoda
#

👍

desert badger
#

K

#

How I find height

full pagoda
#

using your new equation

#

solve for h

desert badger
#

@full pagoda Ik how to plug it in

full pagoda
#

ok

desert badger
#

@full pagoda I can’t get the answer tho

#

Idk how to use the calculator

full pagoda
#

that might be a problem

#

you just uhh

#

type

desert badger
#

I can give u the number can u try it

full pagoda
#

you can use the bot here

#

,w sin(50 degrees)

obsidian monolithBOT
desert badger
#

44/sin 58 (sin 29

#

That

full pagoda
#

your syntax is not the best

desert badger
#

Wym

full pagoda
desert badger
#

Can u help me plug that in

full pagoda
#

are you meaning $\frac{44}{\sin{58}}\sin{29}$

obsidian monolithBOT
#

a disappointing son

desert badger
#

Yes

full pagoda
#

,w (44/sin(58 degrees))sin(29 degrees)

obsidian monolithBOT
desert badger
#

Ty

#

Got it right

#

@full pagoda r u good with stats

snow ravine
#

ayo why is the derivative of sin = cos

uncut mulch
#

you can try differentiating by first principles

hushed sphinx
#

How is that PREcalculus?

uncut mulch
#

its a fine line. difference quotients are pre-calc and then involving limits in the last steps takes it up to calc

obsidian skiff
#

What’s precalculus

sick steppe
#

foundations for calculus

viscid thistle
#

any help

willow bear
#

@viscid thistle do you still need help with this?

willow bear
#

how familiar are you with basic trigonometry?

viscid thistle
#

umm not really fimilar teacher literally did one example

willow bear
#

so your teacher did not even explain to you the words "sine", "cosine" and "tangent", and did not teach you the SOH-CAH-TOA mnemonic to remember which is which?

viscid thistle
#

oh yeah he tought the sine, cos, tan but did not really touch on soh, cah and toa

willow bear
#

...

#

either you have a shitty teacher or you just didn't pay enough attention in that one particular class.

#

do the words "hypotenuse", "adjacent" and "opposite" sound familiar at all to you or are they completely alien

viscid thistle
#

i know what they are

willow bear
#

okay but you don't know the definitions sin(θ) = opp/hyp, cos(θ) = adj/hyp and tan(θ) = opp/adj? is that what's happening?

viscid thistle
#

Yes but is it the same thing for this

willow bear
#

what do you mean by "the same thing"

viscid thistle
#

Do I use them to find x

#

Bc I think the degree is throwing me off

willow bear
#

you are expected to use one of them to find the value of x, yes.

#

you are also supposed to know what the value of sin(30°) is.

viscid thistle
#

Is it 0.5

full dock
#

1/2 yes

viscid thistle
#

So is it relative to we’re the degree is

willow bear
#

???

viscid thistle
#

nvm i got it

viscid thistle
#

heyy

#

how do i type "sin x cos x = sin 2x" in calculator

willow bear
#

what calculator?

viscid thistle
willow bear
#

read the manual for the casio fx-991ex

viscid thistle
#

and also for the number 6

viscid thistle
willow bear
#

wait, you're not asked to solve these equations using your calculator, are you?

viscid thistle
#

either we solve these equations manually or by using calculator

timber obsidian
timber obsidian
timber obsidian
#

except x = 0

#

or values where sin(2x) = 0

timber obsidian
viscid thistle
timber obsidian
# viscid thistle

y = (x+2) / x
yx = x+2
x(y-1) = 2
x = 2/(y-1)
therefore inverse of f(x) = 2/(x-1)

timber obsidian
viscid thistle
viscid thistle
vivid void
timber obsidian
# dim lodge

let cos x = y ( for ease of typing )
4y^2 = 3
y^2 = 3/4
cos ( x) = root(3)/2
x = pi/ 6
x = 11 pi/6

timber obsidian
timber obsidian
timber obsidian
timber obsidian
viscid thistle
timber obsidian
#

sin(x)/ cos (x) = tan(x)

viscid thistle
#

or is it the rule or something to make it like that?

#

im sorry for asking too much :( i kinda dont get it

timber obsidian
#

sin(x)cos(x) = (sin(2x))/2

vivid void
#

yes because that’s what makes them equal

timber obsidian
#

there is one using triangles and another using euler’s fomula

viscid thistle
#

what about the euler's formula

timber obsidian
viscid thistle
#

is this the euler's formula?

viscid thistle
toxic cradle
#

any resources for pre calc?

viscid thistle
#

aops

tight compass
#

Probably khan academy, Stewart’s book

broken pelican
#

correct me if im wrong but
for example, the given is 30°

if the question is "find the SMALLEST POSITIVE co-terminal angles", then the answer is 390°

if the question is "find the SMALLEST NEGATIVE co-terminal angles", then the answer is 330°

#

is it correct? idrk my answer on the second part

queen ermine
#

the wording on the second question is annoying but I’m assuming it’s asking for the closest co-terminal to 30° and if it is you’re answer is correct.

broken pelican
#

thank you

#

and uhhh sorry bout that

timber obsidian
# viscid thistle can you explain it<:happy_cry_cat:636407813144576010>

it would take a while plus my ipad is not with me, just try expanding the brackets out and you’ll see it yourself. or you could simply accept the identities. you can still try expand them. do you know e^ix = cos(x) + isin(x) right? that’s how you get the first line. substitute these values in.

timber obsidian
shy helm
#

Anyone know how they would go about solving this? thanks

sick steppe
#

you have a quadratic in x

#

so you want the quadratic to have no roots in R.

hushed sphinx
#

You also want the leading coefficient to be negative, such that the parabola points downwards.

potent raft
#

question about #23 on this review, do I cancel the LNs leaving me with x = (y - 4)^5 or am I meant to do something else

hushed sphinx
#

Do you mean y = (x-4)^5?

potent raft
hushed sphinx
#

Hmm, it's strange to ask about the "given function" when the formula then doesn't define a function but just a relation between two variables ...

viscid thistle
timber obsidian
#

as in the thing should be <0

tender quarry
#

can anyone help me with parabolas in a call?

viscid thistle
viscid thistle
#

if possible could we hop in a call so i can get a full understanding

uncut mulch
#

convert <LKM to radians and apply the formula for arclength

viscid thistle
vivid void
#

yes, what do you think you’d do next

viscid thistle
#

umm Substitute

uncut mulch
#

write down the formula you intend to use

viscid thistle
#

is there away to do it in the server

uncut mulch
#

take a snapshot of a formula online / draw in paint / type it out in text properly with sufficient and appropriate notation

viscid thistle
uncut mulch
#

bad notation at the end

#

it looks like you crossed out r at the end
and your final line isn't an equation telling you exactly what r is

#

sure, 36/3 = 12. but so what?

viscid thistle
#

is the answer 12

uncut mulch
#

simplify your equation properly and it'll tell you

#

you'll either reach something that tells your
r = 12 or r = something else

viscid thistle
#

r=12

uncut mulch
#

yes

radiant zodiac
#

how

#

idk how to mess with that tan3x

#

imma isolate it

mellow tapir
#

hey guys this is on my friend's homework im not really sure what would be the answer

limpid nest
#

so tan3x = 1

#

sry, -1

#

3x = y

#

so y = 45

#

so, therefore x = 15

#

15 degrees

compact tulip
compact tulip
timber obsidian
timber obsidian
timber obsidian
timber obsidian
tepid cloak
#

any desmos experts here knows how to shade this shape?

marsh cipher
#

@tepid cloak use inequalities

mellow tapir
fickle robin
keen eagle
#

Can someone explain me this question

#

Like I dont understand what we are suposed to do

tight compass
# keen eagle

I remember you, I told you before to go to desmos and play around with different transformations of functions to understand how to solve it. Also read your notes/book on it to understand it.

hushed sphinx
#

There are three operations you're being asked to do in sequence. Can you do the first one?

keen eagle
#

like I did with 2^x

#

then 2^x + 2

proper dome
#

Anyone else doing precal 1 and 2 in one semester?

tepid cloak
#

help how do I shade the unshaded area (the inside of the rectangle) in this figure?

uncut mulch
#

consider first splitting the region into two parts

#

and isolate y for each circular arc

tepid cloak
#

how

willow bear
#

wait are you required to do it as an integral

#

can't you just subtract the areas of both quarter circles from that of the rectangle

#

@uncut mulch @tepid cloak

uncut mulch
#

they wanted to shade it in desmos

#

not calculate the area from what i interpreted

#

like

willow bear
#

oh shade

#

my bad

#

right so this region is defined by four inequalities
$$\begin{cases} \left(x-16\right)^{2}+\left(y-8\right)^{2} \geq 1 \ \left(x-19\right)^{2}+\left(y-12\right)^{2} \geq 9 \ 16 \leq x \leq 19 \ 8 \leq y \leq 12 \end{cases}$$

obsidian monolithBOT
willow bear
#

or six inequalities i guess

#

min( (x-16)^2 + (y-8)^2 - 1, (x-19)^2 + (y-12)^2 - 9, x-16, 19-x, y-8, 12-y) ≥ 0

#

@tepid cloak sorry for the double ping but

willow bear
#

?

#

did you input the ineq as i typed it

tepid cloak
#

im not really good at desmos

uncut mulch
#

type
min( (x-16)^2 + (y-8)^2 - 1, (x-19)^2 + (y-12)^2 - 9, x-16, 19-x, y-8, 12-y) ≥ 0

tepid cloak
#

oh

#

it worked omg thanks!

willow bear
#

swap out the equation of the bigger circle

tepid cloak
#

oh I got it

#

thanks

timber yarrow
#

Hey guys does anyone know how to do no. 3?

astral prism
#

did you distribute the negative?

timber yarrow
#

I used sin(A-B)

tepid cloak
#

does anyone know how to shade the red line on this figure?

trim burrow
#

this is kinda unorthodox and long but it does the job (obv you can fix the colors)

marsh cipher
glass relic
#

hi, can someone help me to resolve this but using properties of natural log

#

If $2000 is invested at an interest rate
of 3.5% per year, compounded continuously, find the value
of the investment after the given number of years.
(a) 2 years
(b) 4 years
(c) 12 years

willow bear
#

@glass relic what do you mean

#

did you receive explicit instruction to do this "using properties of natural log" under threat of punishment?

hushed sphinx
#

Does "compounded continuously" mean that after one year $100 has grown to $100·e^0.035, or that we select a rate of continuous exponential growth that will make $100 reach exactly $103.50 after a year has passed?

willow bear
#

i would think the former

hushed sphinx
#

Hmm, that agrees with what Google seems to be telling me.

hushed sphinx
#

I'm not -- just musing after reading Andrusita's question.

teal plinth
#

is anyone around

#

need a little help

viscid thistle
#

what help you need

teal plinth
#

how do you find b. I haven't done precalc in a long time

viscid thistle
#

bro this is the same lesson

#

i’m struggling with

#

that’s quadratic functions right?

teal plinth
#

yep

#

actually nvm i found the answer to b

viscid thistle
#

that’s like the lesson i’m struggling with and i have a test tomorrow

teal plinth
#

not well enough to help you

viscid thistle
teal plinth
#
#

checkout this channel. he explains stuff really well.

#

just type the type of problem and search if he has (mostly likely does)

#

thats how I get thru my math classes

viscid thistle
#

aight man thanks

teal plinth
#

np

vagrant lintel
#

Hi, anyone can help me finding this?

vivid void
#

it’s a linear function

#

so just find the slope

#

and then find what the added constant is

vagrant lintel
#

It's not lineal.

vivid void
#

yeah it is

#

we have two points

#

wait oh gosh

#

,w plot (3.3,8.9),(0.38,40)

obsidian monolithBOT
vivid void
rustic forge
willow bear
#

the person left

vapid stratus
viscid thistle
uncut mulch
#

supposedly there's an image that comes with the question

stuck lark
#

@strong ermine dont shitpost here

strong ermine
#

Ok

#

Precalc meme

hollow vapor
#

PLUS CCCC

lean cove
#

Can anyone help me really fast? I don't remember what the thing on the right of the 8 is for

#

also it's not a quiz for my class just got an example off khan academy

uncut mulch
#

to indicate which sides you're approaching from

lean cove
#

So - would come from the left?

uncut mulch
#

yes

vivid void
#

$x\to 8^-$ means you’re approaching 8 from values that are less than 8

obsidian monolithBOT
#

quantum

vivid void
#

so the left

lean cove
#

Oh ty that makes sense

deep pewter
#

HELP

viscid thistle
#

<@&286206848099549185>

heady mango
viscid thistle
steel fern
#

I have an old calclulator that my dad used in college. A casio 7000-GA is that something i could now days ?

#

if not waht should i buy calculator wise for precalc

uncut mulch
#

pretty much any scientific calc is good enough for precalc

steel fern
uncut mulch
#

a graphing calc can do what a scientific calc can and more

tepid cloak
#

how do u read this again

willow bear
#

this looks like desmos notation for a restriction

tepid cloak
#

yeah

runic ravine
#

can someone help? the topic is pascal triangle

#

<@&286206848099549185>

tight compass
# runic ravine

You can either write out the pascal triangle up to 5 and 9 to figure it out or just compute it explicitly using combination formula.

fiery creek
obsidian monolithBOT
#

mniip's foe

fiery creek
#

do you know how to do factorials?

crystal stream
#

isnt the formula dA/dr = dA/dt * dr/dt

fiery saffron
#

dA/dt=dA/dr•dr/dt is the correct chain rule

hoary rose
#

I dont get wat I did wrong

#

the steps look correct yet for some reason I got the wrong answer

#
3h^2 - 22h + 7
3h^2 - 21h - h + 7
(3h^2 - 21h) + (-h+7)
3h(h - 7) - 1(h - 7)
(3h - 7)(h - 7)(h - 7)
#

I dont know what order the factored out numbers for 22h should be in

#

so I dont know how to factor it correctly

heady mango
#

you did everything right until after the last line. how would you factor this:

#

$3h \cdot a -1 \cdot a$

obsidian monolithBOT
#

Taltost

cold kestrel
#

lmao

viscid thistle
#

huh

#

hmmmmm secx?

#

No

#

3sec(x/pi) or smth

viscid thistle
#

pix?

#

Yeah?

snow axle
amber badger
#

Yoo can someone help me understand this

#

Im lost

hushed sphinx
#

Do you have a place to look up trigonometric product formulas?

#

(at least you presumably have Google).

amber badger
#

i dont think so

#

this was given as a quiz on paper in class and your allowed one cheat sheet

hushed sphinx
#

If this kind of questions are on the quiz, the trigonometric product/addition identities should definitely be on your cheat sheet.

amber badger
#

ok

#

are they these

#

ohhh i get it

#

you just have to find which ones correspond

#

my bad

hushed sphinx
#

Yes, that's the ones.

#

There should be ones that take sums to products too, for the second part.

short pilot
#

can someone explain me how i find the nht term

sick steppe
#

what have you tried/thought/noticed?

short pilot
#

i tried to find the d like others excersice

#

but my book do something and doesnt show a formula or something

sick steppe
#

Geometric Sequence/Progression is the key term

frank acorn
warm nebula
#

@frank acorn expand it using foil

tight compass
#

Expand it using distributive property which says a(b+c) = ab + ac.

#

Apply it to this (a-b)^2 or just (a+b)^2 then you have a nice quicker way to always expand expressions in that form.

meager cairn
viscid thistle
# frank acorn

Expand this using (a-b)² = a² + b² - ab . There you go :-
(2x-3)²
=> (2x)²+(3)²-2×2x×3
=> 4x²+9-12x

serene pewter
#

The range of this function would be [3,0) right?

vivid void
#

no

serene pewter
#

what the heck

#

What am I doing wrong?

vivid void
#

what’s the largest y value

serene pewter
#

3?

#

oh wait

#

nvm

#

hahaha

vivid void
viscid thistle
#

Wth are h&k?

hushed sphinx
#

Hopefully that is explained on one of the preceding pages; otherwise you're sunk.

viscid thistle
#

?

hushed sphinx
#

There's no standard concept of "parameters h and k" for a function. It must refer to something defined specifically in that book/course/module/test/whatever.

hollow idol
#

I think question 2 explains what h and k are