#geometry-and-trigonometry

1 messages Β· Page 62 of 1

trail tendon
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i always thought if you turn something into a series its called series decomposition

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maybe thats something idfferent πŸ’€

faint pasture
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Nah i was talking about repeteadly using sin(a+b) πŸ’€ it was the only real way to approximate before calc came sooo i mean yea

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It is tedious but uea

faint pasture
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The other 3 are just reciprocals of these

trail tendon
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sin, cos, tan?

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you know that sin(theta) is adjacent/hypotenuse from theta?

faint pasture
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Look into the unit circle definition

trail tendon
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yeah

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learn the other three trig functions

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then look at unit circle

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and memorize the values

trail tendon
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cosecant

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(csc)

faint pasture
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Cosecant or simply csc

trail tendon
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i mean

faint pasture
trail tendon
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how do you know sin(1 deg)?

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and cos(1 deg)?

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if you're solving for a side, and you know theta and the length of one side, and the unknown side is in the denominator if you use sine, you can use cosecant instead

faint pasture
# trail tendon how do you know sin(1 deg)?

For all purposes except being rigorous i just let it = 0 lmaooo

If not using series then i guess there isnf any real way too calculate it except solving the 45th degree polynomial

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Oh wait

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We know sin(18)

trail tendon
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yea

faint pasture
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Boom we just have to solve a 18th degree polynomial now

faint pasture
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Extremely

trail tendon
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i mean theres trig identities

trail tendon
faint pasture
trail tendon
faint pasture
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Since we know sin6 we know sin 2

trail tendon
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so wait

faint pasture
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Since we know sin 2 we knos sin1

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Aha

trail tendon
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ur assuming sin(1 deg) = 0?

faint pasture
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Ez pz lemon squeazy

faint pasture
trail tendon
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πŸ’€

sharp ruin
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Heyy what's going on here?
Couldn't sleep so thought of checking here

trail tendon
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as you should be

sharp ruin
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Lol man sleep talking math
You're wild

faint pasture
trail tendon
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πŸ’€

faint pasture
sharp ruin
faint pasture
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We can

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But you see if we do

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Then thatd mean sin3 =0

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Then thatd mean sin 30 =0

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Soo shit just breaks

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XD

sharp ruin
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No it doesn't
Trust me
Small angle => Take the shit to radians

faint pasture
sharp ruin
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Or just say zero and move on

cunning lion
faint pasture
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We live in 500 BC

trail tendon
faint pasture
sharp ruin
trail tendon
faint pasture
sharp ruin
faint pasture
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Needs taylor series

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I just told you-

sharp ruin
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Lemme tell you something
Pythagoras wasn't a real person πŸ’€

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Believe me he really wasn't

trail tendon
faint pasture
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We know sin 18, then we know sin 6, then we know sin2, then we know sin1 and since we know sin 1 we know all integer values

sharp ruin
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It was a cult that called themselves Pythagoreans and had an imaginary idol
They worshipped math

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I'm not even lying

sharp ruin
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There are literal articles about this

trail tendon
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the weird thing is we're taught math backwards ._.

faint pasture
faint pasture
sharp ruin
trail tendon
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you think you're joking...

sharp ruin
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Or history enthusiast

trail tendon
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but honestly not a bad idea, to an extent πŸ€”

faint pasture
sharp ruin
trail tendon
faint pasture
sharp ruin
faint pasture
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Like no you dont need to teach the kids integration by parts or shit, but telling them that they can integrate a function to find area under the graph and teaching them the basic ones could be nice

sharp ruin
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It really does and that is wild

trail tendon
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its not hard πŸ’€

faint pasture
sharp ruin
faint pasture
trail tendon
faint pasture
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I have been doing graphs since lile 2nd grade

sharp ruin
faint pasture
sharp ruin
faint pasture
faint pasture
faint pasture
sharp ruin
trail tendon
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dude i feel like it doesnt even matter how old u are lol

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unless ur like 3

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but at a certain point your brain is good enough to be able to understand

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so liike

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why not

faint pasture
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Hmmm function takes in a value and returns another value

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That is all it is

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Nice

sharp ruin
faint pasture
faint pasture
sharp ruin
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Okay then just a sec

faint pasture
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Lmao

trail tendon
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i dont mean skip to calculus

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i just mean teach it faster πŸ’€

faint pasture
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I mean there wont be any proof

trail tendon
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exactly

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πŸ’€

faint pasture
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(Your ed system sucks then- we were taught algebra in 6th grade so like 10?)

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We had stats and probability and shit before that

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Not here

trail tendon
sharp ruin
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I found somewhere it was written that Pythagoras was a real person and he created that cult πŸ’€

trail tendon
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you can learn that during/pre-kindergarten

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bruh

faint pasture
sharp ruin
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That's an year or 2 later I guess but not too late in my opinion

trail tendon
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πŸ’€

faint pasture
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I mean sure but its set up as it was required? If kids seemed to understand it in like a year they would shorten it, but it is the kids who are dumb not the tchrs-

sharp ruin
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Seems okay to me
Why are you guys so pissed about being taught slowly lol

faint pasture
sharp ruin
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I mean all of the systems eventually throw students at the same level when it comes to university

trail tendon
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human, to be exact

faint pasture
faint pasture
sharp ruin
faint pasture
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I hacked youπŸ™ƒ (you said so above lmao)

faint pasture
trail tendon
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guys linear alg or multivariable first

faint pasture
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Lmao i even know your religion

sharp ruin
faint pasture
sharp ruin
trail tendon
faint pasture
trail tendon
faint pasture
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Are you suree? 🀑

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Maybe you are and you just dont know

sharp ruin
faint pasture
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I am in here rn

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Its fun

sharp ruin
sharp ruin
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Then you should probably learn philosophy
You might wanna kill yourself early πŸ’€
Sorry what the hell did I just say

faint pasture
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You try to go in space, i try to go below earth (earth is flat obv so i can go below it duh)

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Nah earth is just a pringle

sharp ruin
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It might be a snickers bar

faint pasture
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Ni-

sharp ruin
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Nickers πŸ™‚

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We will be right back (Music plays)

faint pasture
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this user has been arrested by the fbi for using the n word without a pass

sharp ruin
faint pasture
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Are those rsndomly chosen too?

sharp ruin
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Naah obviously not
That's dumb

faint pasture
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πŸ’€

sharp ruin
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Do USA and China first

faint pasture
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Austin

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Sydney

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Melbourne

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Hiroshima

sharp ruin
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Aaah no man not Australia

faint pasture
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Nagasaki

sharp ruin
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Berlin

faint pasture
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Osaka

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Beijing

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Shanghai

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Taipei

sharp ruin
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New York πŸ’€

faint pasture
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Mumbai

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Macau

sharp ruin
trail tendon
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Perth

sharp ruin
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Canberra?

trail tendon
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i don't know australian cities

faint pasture
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I know like 0 australian cities

sharp ruin
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Which one is remaining then

trail tendon
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google time

faint pasture
sharp ruin
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What the hell is that?

faint pasture
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Sounds like spanish

faint pasture
sharp ruin
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It's Australian and no cricket matches I've heard being played there

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Doesn't even qualify as Australian

trail tendon
faint pasture
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Ulanbatar was mongolia right?

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And which country was lagos in?

sharp ruin
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My man took out the most underground cities from the whole world just to confuse us πŸ’€

faint pasture
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Ulaan bataar is the capital iirc

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Lagos was in the news a couple years ago

sharp ruin
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Still not like DC famous or Delhi famous

faint pasture
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Seattle is seattle

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Bangkok is bangkok

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Australia perth

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Oh lol

sharp ruin
faint pasture
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That was quick

sharp ruin
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China from Asia

faint pasture
sharp ruin
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I meant Shanghai lol

faint pasture
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For europe bern

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Lol

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Frankfurt

sharp ruin
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Pls now do berlin

faint pasture
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Berlin

sharp ruin
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Europe then
Is it done already?

faint pasture
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I know 2 damn german cities

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And its not one of them

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So yea

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Oh-

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Lmao

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Africa cape town

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Wtf lmao

sharp ruin
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Nice man

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Everyone deserves to die here

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So that we can know if it's a simulation or not

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One small sacrifice for the bigger fact

grave pond
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Could we perhaps try to walk the conversation back in the rough vicinity of the channel topic?

faint pasture
wise nest
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chat i searched up 25/35 questions on my geo final yestarday

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i think i passed fr

maiden brook
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hopefully not during it right

upper karma
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hey just a question about a graph, are these graphs possible(beside circle graph) to get through formulas? the unit circle can be graphed using sin and cos but the following waves used to graph other the shapes I had not been able to find any formulas that represent these shapes. Could they just be demonstration graphs for learning trigonometry? all helps appreciated

I ask this question because like the unit circle I was hoping to draw a square in desmos without many steps

burnt crescent
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no idea though i could be wrong in thinking theyre related

hoary totem
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u will see its just a piecewise function involving regular trig in the end

upper karma
grave pond
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It looks like you're letting a ray from the origin sweep around with constant angular velocity even though that means the point on the polygon moves with a varying speed, right?

upper karma
grave pond
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I'm fairly sure you'll need to define your functions by a case analysis according to which side of the polygon your ray hits at each given angle.

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For each of the sides (except horizontal one) the expression in the corresponding case becomes a segment of a scales and moved tangent function.

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(But for the hexagon and upwards that will look pretty much like straight lies anyway, so you could just cheat and interpolate linearly between points on a sine curve).

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I ask this question because like the unit circle I was hoping to draw a square in desmos without many steps
Oh, I just saw this. I don't think you'll find anything that's shorter and (especially) clearer than drawing the sides of your square one by one.

upper karma
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ah well darn, I suppose now getting into more complex math it would probably be the easiest way. I appreciate your insights on this, Im not too familiar with some of the terms mentioned, mathwise im still a bit new but ill look into what you said, I think I understand what you are saying though by using segments to then use interpolation to find a function that matches the goal. I will probably stay with drawing the sides then for now, mission continues...

lime dune
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for what troposphere described you primarily need trig stuff

hoary totem
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i did it

upper karma
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oh my gosh

hoary totem
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i drew a square using c(x) (square-cosine) and s(x) (square-sine)

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c(x) and s(x) are graphed too

upper karma
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you have really done!

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thank you!

hoary totem
upper karma
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Im unfamiliar with the math or maybe need more time to understand how its been done but it is really impressive. I really appreciate your time working out the problem , I am assuming they are the piecewise functions you had been talking about earlier, I suppose now the mission is complete

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now that the problem is solved I suppose it is just a matter of learning how, but yeah, thank you for showing me the way

hoary totem
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i implore u to figure it out urself

upper karma
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count on it, I am really interested in learning to do it, maybe even achieving more shapes too

hoary totem
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the parts where its not 1 and -1, draw a small triangle

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work out the geometry

upper karma
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I think Im beginning to understand, ill keep in mind drawing out the triangle, I will experiment in desmos once im able and see

hoary totem
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i only made half of it

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because... the rest seemed like a waste of time

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the hexagon isnt rotationally symmetric by 90 degrees

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which is why the "cosine" and "sine" functions dont look similar

twin crag
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is k = 1/60? that feels wrong ngl

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i used the formula for the period of a sine wave

2pi/A (where A is part of sin(Ax))

then did 2pi/A=120pi

A=1/60

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oh wait

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this isnt a sine wave

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uh

hoary totem
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well

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the particle moves in a circle

twin crag
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yeah πŸ’€

hoary totem
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u should recognize that this is the parametric equation of a circle

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and uh

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well it moves a distance of 120pi every second

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which means it made... 120pi/2pi = 60 revolutions in 1 second

twin crag
hoary totem
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so the period is 1/60 hertz

twin crag
hoary totem
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the answer is not 1/60

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u need to convert from hertz (1 rev/s) to rad/s

twin crag
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thanks

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is there a way to convert hertz to radians πŸ’€

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oh

hoary totem
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yes

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tbh

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wait i dod this wrong

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the radius of the circle is 6!

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so the circumference is 12pi

twin crag
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oh so 10 hertz

hoary totem
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which means the distance of 120pi is only 10 revolutions

twin crag
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wait would i show this as 1/10
or just 10

hoary totem
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its 10 revolutions per second

twin crag
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ok so just 10

hoary totem
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so the period is 1/10

twin crag
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oh

hoary totem
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so wait yes

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its 10 Hz

twin crag
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ok ty

hoary totem
#

convert to radians

upper karma
# hoary totem the hexagon was harder

I understand now I believe, I suppose lots of trial and error was required to get the hexagon to appear, half of it though may even be enough though maybe changing one of the points to negative could just flip the graph over and save the extra time. Even on the square its a bit time consuming to sort of sculpt a result out of these graphs

lime dune
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you don’t need trial and error for this, look up parametric curves to see how they did it

upper karma
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I think ill check into this for the moment

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I will see what I can do but I do think they could be pretty helpful for these graphs

hoary totem
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yeah it did not involve trial and error for me

silver fable
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Hi I have two intersecting lines (p0, p1) and (p2, p3) and a radius (R) I need to find the center of the circle tangent to both lines, can anyone help me?

faint pasture
shut bronze
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are there not infinitely many circles tangent to any two given lines

shut bronze
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even so isn't there like 4

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and infinite or 0 if they're parallel

faint pasture
faint pasture
shut bronze
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oh true

faint pasture
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Hmmm

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Well the problem is rather doable.if yk the formula for distance between point and line

shut bronze
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perpendicular distance formula

faint pasture
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Hmm

shut bronze
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|ax + by + c|/sqrt(a^2+b^2)

faint pasture
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Yea

silver fable
silver fable
faint pasture
silver fable
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Is there like a direct formula or should I solve the line equation? It's for programming purposes

shut bronze
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if its finite wouldn't you have to check all 4 and see which ones have the tangent points actually on the line

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surely there's an easier way

faint pasture
silver fable
shut bronze
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yeah try that

silver fable
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Also there is one case, one if the lines is always perpendicular to X or Y axis

shut bronze
faint pasture
shut bronze
#

what method

agile slate
#

I was messing around with topology, trying to understand the high level overview (i'm a math newb).

After looking at sheaf theory, ring theory, e.t.c, is it safe to say that we are basically trying to model the behaviours of certain shapes and movements/processes that have physical existence using numbers? (for ex. the drum vibrating problem)

faint pasture
shut bronze
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absolute value is on both sides so shouldn't it give 4 results

faint pasture
faint pasture
agile slate
#

Sorry again, where should i post it?

faint pasture
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Then solving the linear equations

faint pasture
agile slate
#

alright, thank you anyways

shut bronze
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if you use radius you get 4 solutions

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because instead of |...| = |...| you have |...| = |...| = r

faint pasture
#

Hmmm

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Isee

echo beacon
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i got 50 but comment section is all over the place

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wait

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i’m lost

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beauty

vernal sapphire
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Should be 40

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I think

shadow depot
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Yeah it’s 40

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You end up with an equilateral triangle when you draw a line on the right side. The 50-80 line and one of the sides of the triangle produces an isosceles triangle, so you end up getting x + 30 = y, and x + y + 70 = 180

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So x is just 40

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I feel like I cheated though because I used sin(30) = 1/2

heady kiln
trail tendon
#

cuz thats not possible because you only know 2 of the angles

heady kiln
trail tendon
#

you mean 50, 70, 80, 60, and ? ?

echo beacon
trail tendon
#

bruh

echo beacon
#

it just cuz i was doing it during my lunch break

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i was half eating half doing it

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on my phone mentally

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wait

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i’m so confused

heady kiln
trail tendon
# heady kiln πŸ‘

50 + 70 + 80 + 60 = 260
360 - 260 = ? = 100
but the answer is not 100, why do you think this method ^ would work?

echo beacon
#

nvm i got it

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with my dads help violet_approves

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so real

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bro saw that it could be on a circle

chilly pasture
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Anyone have any advice on this problem? I think this has to do with trig identities but im unsure what im doing wrong.

gentle haven
#

First thing I can think of is use the quadratic formula

obsidian harness
#

not -8

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Oh also there are infinitely many solutions if your domain is the real numbers

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Yeah so you need to be adding +n pi to your 2 principal solutions

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just arctan them and ye

olive jetty
#

is this a construction of a median?

olive jetty
obsidian harness
#

this is a median, so no

olive jetty
obsidian harness
#

those two lines are definitely not parallel

olive jetty
#

is it a perpendicular line?

obsidian harness
olive jetty
digital pebble
#

yo @everyone, anybody willing to help me for my hw

gentle haven
obsidian harness
#

basically you have one point A in the diagram, and not two points say C and D

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ofc you construct the perpendicular to point A by using your compass to mark out equidistant points C and D

gentle haven
#

Oh wait I just realized it's not a line segment

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No bisector then

obsidian harness
#

mhm

tall coral
shut bronze
#

i feel like if you remove that restriction all of this still holds

tall coral
shut bronze
#

well yeah im pretty sure if you allow moving the point at the bottom there than all of these can hold with varying values for the missing angles

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you need to somehow use that fact

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sounds like trigonometry

trail tendon
tall coral
#

idek what I am doing anymore iguohfdszaOL

grizzled hornet
tall coral
#

not from what I got

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I just got it

grizzled hornet
tall coral
#

Here's what I got (quite a convoluted model, but it's apart of the process)

trail tendon
grizzled hornet
faint pasture
tall coral
grizzled hornet
#

@tall coral how did you get 70 on the upper triangle?

faint pasture
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Oh nvm

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I saw it

trail tendon
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i dont understand the blue 70 degrees

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i think its gotten from the blue 120

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but idk how they got the blue 120

faint pasture
#

Me neither

trail tendon
#

unless its the arc degrees

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in which case idk what that has to do with the angle

faint pasture
#

I just saw the isoceless thing

grizzled hornet
tall coral
#

I thought opposite angles of a cyclic quadrilateral add to 180

faint pasture
#

But the thing is its not neccessarily a cyclic quad

trail tendon
#

whats a cyclic quadrilateral

trail tendon
#

oh

faint pasture
#

Since the green point can move to anywhere out of circle

grizzled hornet
faint pasture
#

And shit still satisfies

faint pasture
trail tendon
#

a quadrilateral inscribed in a circle, where all the vertices are touching basically?

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ah

faint pasture
#

Hmm

trail tendon
#

yeah the opposites would add to 90

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but yes we dont know

tall coral
tall coral
#

the orange 80 degrees would change if the green point moved

tall coral
#

this green point?

faint pasture
#

Green point as in the top right ome

faint pasture
tall coral
#

oh

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moving that would change the red 70 degrees then

faint pasture
#

So how do you know thr current configuratiom leads to it being cyclic?

tall coral
#

let me clean the model up a little with geogebra

faint pasture
#

Ill be back in a bit

tall coral
#

oh wait I see where I went wrong

faint pasture
#

Angle chasing is half the reason i despise geometry

faint pasture
tall coral
#

just more lines

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if I can prove these two are equal, then the whole thing comes together nicely

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no wrong angle

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if I show all this is true, we're gold

trail tendon
#

no

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thats not what u ment

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wait yes maybe

faint pasture
#

Guyz isnt geometry so easy

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✨

tall coral
#

wait that wouldn't even work

trail tendon
#

i know like

faint pasture
trail tendon
#

you can pick "hard" problems from any one of them

trail tendon
trail tendon
faint pasture
tall coral
#

let me start over

tall coral
#

I'm ginving up tonight, I got nothing.

faint pasture
hoary totem
#

took about 5 mins with a friend

faint pasture
hoary totem
#

cuz of the equal lengths and also the right triangle

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it must be cyclic

faint pasture
echo beacon
#

i would never think of it

echo beacon
hoary totem
#

...because of the equal lengths?

echo beacon
#

and there is a 90 degree angle

hoary totem
#

and the right angle?

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i said so

echo beacon
#

yeah

hoary totem
#

yeah

echo beacon
#

and then

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the equal length at 50 80

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radius

hoary totem
#

and then it was obvious

echo beacon
#

bro I WOULD NEVER THINK OF THAT

hoary totem
#

that its cyclic

echo beacon
#

HOW DO U GUYS

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THINK OF THAT

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😭😭😭

hoary totem
#

it was the obvious next step

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lol

echo beacon
hoary totem
#

idk what to say

echo beacon
violet vale
#

hi

sturdy stone
#

are you the real doctor house

nocturne remnant
# echo beacon THINK OF THAT

It kinda looks like concyclic + there’s not really another easy way to do the problem if it’s not concyclic

deft drum
#

I am unable to find another answer from trigonometric and algebraic manipulations. Please help me find another option (not the answer directly, but an approach)

#

Currently the expansion of $(\cos x + \iota \sin x)^3$ looks like $$(\cos^3 x - 3 \cos x \sin^2 ) + \iota (3 \cos^2 x \sin x - \sin^3 x )$$.

somber coyoteBOT
#

ĐARKγ€…MÁTTER

faint pasture
deft drum
#

Yes but there is one more correct answer

faint pasture
deft drum
#

Ah using cos^x + sin^x = 1 identity

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These are too hard for me to remember, I will check

faint pasture
faint pasture
#

give me a challenge for trig (not directly related to triangles or other geometric figures)

chilly pasture
faint pasture
#

,w calc arctan(8)

somber coyoteBOT
faint pasture
#

unless you wanna give this as an answer that is

mellow quest
#

∠BAC = 60 ∠AHD = 51
H - orthocenter
D - incenter
∠ABC = ???

formal geyser
#

I got no idea how to solve it

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I mean, i calculated the 120 angle at the top of bottom triangle

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And 60Β° angle also

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But it didnt help

faint pasture
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too find the length of the bisector

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then cosine rule in upper triangle

tall furnace
#

Hi , I think u can find the solution easily with this figure

faint pasture
tall furnace
#

all the angles O=60

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so X//Y

faint pasture
tall furnace
#

um... if X//Y, all Os=60

faint pasture
tall furnace
#

so right-bottom tri's angles are 40,60,80

mellow quest
grave pond
#

How do you get the angles to the left of the vertical line there?

grave pond
#

Can you explain a bit more?

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I see there's a kite in your diagram, but not how you conclude anything about the angles to the left of its vertical diagonal.

mellow quest
#

guess I was wrong

grave pond
#

Crunching trigonometry in a coordinate system says the top angle of the triangle is 87.88Β° rather than 90Β°, so your numbers would look almost correct on a scale drawing.

plain nexus
#

please help me

#

If you can answer in Turkish, translate it into Turkish

subtle birch
#

is english fine?

subtle birch
#

then find <ACB

#

then use law of cosines again to find AB

#

and at last use law of sines to find x

worthy orchid
#

X=26

tall coral
#

OHH I FORGOT ABOUT MY SPECIAL TRIANGLES

#

UGHHHH

humble lily
#

@heady token

verbal moth
#

hi im new to discord, can anyone help with taking pictures and sending it to the group, im also on computer

bronze owl
humble lily
#

aaaaaa

#

yes

bronze owl
#

You can use the angle bisector theorem to find this

#

4/3 = x/9

#

Same for the other triangle

obsidian harness
#

that's the easiest way

humble lily
#

Yay

bronze owl
#

Not exactly

#

You can have an angle bisector that divides it into two triangles that arent similar

#

But the a proof of the theorem does involve similar triangles

#

So pretty close

cold stream
#

why is it bΒ²+cΒ²=aΒ² in the Pythagorean identity sinΒ²+cosΒ²=1 and not aΒ²+bΒ²=cΒ²?

#

or its just how my teacher put it

maiden brook
#

what?

#

b^2 + c^2 = a^2 in a right triangle just means the side with length a is the hypotenuse

#

still valid

cold stream
#

aight

faint pasture
#

They can mean anything

cold stream
#

aight

#

i just was a little bit confused

severe temple
#

Hey uh sorry but can you explain something to me? I have to prove that if aΓ—tan(A)+bΓ—tan(B)=(a+b)Γ—tan((A+B)/2) in a triangle, then a=b and for some reason I get a/b=-1. If the first 2 pluses would be replaced by minuses I think it would work...? I can show you what I wrote but handwriting is really bad and I use romanian notation for trig functions. (Like tg instead of tan)

heavy lava
#

I have test tommorow and still confused on how to solve trig equations, could someone help explain a few of these review questions?

wicked jetty
#

Stuck on this

velvet pendant
#

I HAD MY MATH FINAL EARLIER TODAY! IT WAS EASY, I THINK I’M GONNA END THE SEMESTER WITH AN A!!!

velvet pendant
velvet pendant
trail tendon
#

what was it on?

velvet pendant
#

Probability and stats and basically all of trigonometry

trail tendon
#

ayy XD

velvet pendant
#

Well I calculated the score I need on it to end the year with an A

#

I basically only need to get a 30/45 or a D

#

And I prolly got an A on it

#

So yay

#

I ended up completing the entire AP stats khanacademy course to study for it 😭😭😭😭 even tho it was just a mini unit and I’m not even in ap stats

#

Can’t wait for ap calc A and pch next year

bronze owl
fleet compass
#

Has anyone ever done the flvs geometry 1 and 2 I am struggling hard with it if anyone could help out with it.

cold sun
#

how do i use cosine rule to find angles?

#

whats the thing for that again

bronze owl
#

If you already know the lengths of all the sides, isolate the cosine function and then inverse cosine both sides

velvet pendant
#

You can get that by rearranging the law of cosines, which is c^2=a^2+b^2-2abcosC

cold sun
#

ended up rearranging it yea

velvet pendant
#

Oh ok

cold sun
#

thanks

velvet pendant
#

Someone pls verify that
5sin38/sin17 = (-5tan55tan38)/(sin55(tan38-tan55))

(degrees not rads)

weary remnant
#

Just plug it into a calculator

#

?

grave pond
#

If it seems to be true with the calculator, actually proving it should probably start with sin(17⁰)=sin(55⁰-38⁰) and a sum formula, followed by algebra crunching.

red isle
#

what’s the meaning of the distance of non-coplanar straight lines?

faint pasture
#

Any two straight lines will always be coplanar no?

red isle
#

?

grave pond
#

Not in 3d space.

faint pasture
#

Nvm

red isle
#

in 3d space

#

not parallel

grave pond
red isle
#

i'm interested in how to prove it.

grave pond
#

The distance between those two intersections is the shortest possible distance from a point on one line to a point on the other.

grave pond
red isle
#

We haven't learned about spatial coordinate systems yet, can we use the synthesis method?

grave pond
#

Undoubtedly, but I can't immediately rattle off a proof. What is the exact claim you want to prove?

red isle
#

β€œIf the lines are not parallel, there will be exactly one line that intersects both of them at right angles. ”this proposition

fading wing
#

Does anyone know where i can study plane geometry and Trigonometry (ratios, functions, equations, identities)? bec i have a uni addmission test in 2 days and i never studied those in school

lime dune
#

if you're just starting to study these two days before the exam

#

all i can say is

#

you should've started way earlier

fading wing
devout elm
#

demos gone mad'

#

x^x ?!

faint pasture
trail tendon
devout elm
#

how ?

#

so many limites

faint pasture
devout elm
#

why

faint pasture
devout elm
#

(-5/2)^(2/5)

faint pasture
#

Hmm

faint pasture
devout elm
#

maby it just cant calculte it

devout elm
#

\sin\left(x\right)\cos\left(y\right)=\tan3

#

sin(x)cos(y)=tan 3

#

ANY IDEA WHY

faint pasture
#

,w calc tan(3)

somber coyoteBOT
faint pasture
#

Sooo y not

devout elm
#

yha .. trig funtions are weird

faint pasture
devout elm
#

im rn in 9th .. so for me .. i dont understand some things

faint pasture
#

If you know everything then its boring no?

devout elm
#

very true .. my summer holidays are going on and i have target to finsh calculus

#

though sometimes its fun to already know \

lime dune
#

that … sounds like a rather lofty goal

#

don’t rush it

devout elm
#

IKtinktonk

but if i go slow then ill take me 1 year to do it cat_happycry

lime dune
#

realistically if you’re still trying to wrap your head around trig funcs

#

im not sure you’ll be able to do it in a single summer

devout elm
#

uhhhhhhh ............

lime dune
#

don’t rush, make sure you actually get what’s going on before you β€œmove on”

devout elm
#

k.. ill do trig first..
any way to learn trig better ?

#

is there online website ?

#

i cureently use khan acadmy

faint pasture
lime dune
#

it's easier when your foundations are strong

#

which is not always the case

faint pasture
#

Hmm thats true

#

I didnt have to look at the precalc stuff during that month

lime dune
#

yea figured

tribal cobalt
#

I need help with Stereometry. Anyone who understands this? I really need help. tomorrows a exam. :)

shy cape
#

hello

stray junco
#

ive been breezing through my homework till this point i have 0 clue on how to go about this. ive gone through khan academy and everything and i need help with it

#

πŸ™

grave pond
#

Do you know how to compute the area of a sector of a circle if you already have the radius and its central angle? Or the radius and the length of the arc?

stray junco
#

i confused myself alot and i tried converting the central angle to degree but still came out wrong

grave pond
#

Can you explain, with either words or formulas, how you would compute the area if given the radius and an angle in degrees?

shut bronze
#

fraction of area * total area

#

2 pi is 360 degrees

grave pond
#

Great!
So if you insert the known values there, you get the equation
3 = (1/5)rΒ²/2

stray junco
#

thank you guys so much, i finally solved it thank you!

grave pond
stray junco
shut bronze
#

because you phrased it like a question i was just answering you

#

my bad

grave pond
#

I must have sounded insufficiently Socratic. :-)

sacred beacon
#

hI

#

It is a Geometry problem "Draw a plane P and then draw a line and a semi-line on it"
pls help me

harsh wasp
#

So im trying to find how many mm this Colume tappers in relation to the hight so I can get an angle, it's for a wedge that will angle the machine to cut the slope, I was thinking rise over run but idk if I'm using the equation properly.

steep fossil
#

can anyone help me solve these geometry problems πŸ™πŸ™

brittle bridge
#

U gotta be more specific bro

steep fossil
#

sorry ive finished most of that its just these two problems are really confusing me

azure helm
#

How many units apart is any pair of parallel sides of a regular hexagon with side of $6$ units? Express your answer in simplest radical form.

somber coyoteBOT
#

studying_calc_real_analysis

maiden brook
#

any ideas?

azure helm
#

you are asking to me?

#

nah, I dont have enough geometry intuition, can you guys hint me on this?

maiden brook
#

draw a diagram and draw what u want

azure helm
#

mmm I dont have drawing

#

but each side is 6 units

#

and we have 3 parallel pairs

maiden brook
#

select two of them it doesn’t matter

#

draw the segment that marks the distance u r looking for

azure helm
#

its a rectangle

#

now what

#

interesting catthink

maiden brook
#

a rectangle?

#

can u send the diagram u made

azure helm
#

@maiden brook

#

its a equialateral triangle

#

but

#

how do I continue after this?

maiden brook
#

yeah so u want that horizontal distance in the center there that u drew right?

#

if u take one of those two smaller triangles that make up that equilateral triangle, what can u say about those?

azure helm
#

oh yeah

#

by pythagoreas we can get the result if we multiply it by 2

#

basically calculating one of the sides of one of the right triangles

#

anyways, i got ||6sqrt(3)||

maiden brook
#

yes

azure helm
#

how do I solve this ?

#

I tried inscribed angle theorem but didnt do the trick I think

tepid basalt
#

Glad I don’t have to learn this πŸ’€

sand epoch
#

OB and OA are both radii

#

It's an isoceles triangle

#

180-110-2x=0

#

From there it's pretty intuitive

azure helm
#

why isosceles tho?

#

circumcenter propertie?

sand epoch
#

360-100-110=150

#

It's a circle

#

O is the center

azure helm
#

i know coa is 150

#

but

#

what about isoceles

#

why???????????????????

sand epoch
#

If O is the center of the circle, anything line starting at O that touches the circle will be equal to the radius

azure helm
#

wow

sand epoch
#

Wait nvm it's the circumcenter

#

Lol

azure helm
#

no, I got you

#

but why isoceles though

azure helm
#

its isoceles because lines starting at circle and ending in circumcenter is radii

#

anyways I solved, it was 50

#

but I wanted to ask about this one now, if someone can help me a bit

#

The first square below is in position ABCD. After rotating the square $90$ degrees clockwise about its center point, the second square is in position DABC, as shown. Next, square DABC is reflected over its vertical line of symmetry, resulting in the third square in position CBAD. If the pattern of alternately rotating $90$ degrees clockwise and reflecting over the vertical line of symmetry continues, in what position will the $2007$th square be? Write your answer starting with the lower left vertex and continuing clockwise with the other three vertices. Do not use spaces or commas when entering your answer.

somber coyoteBOT
#

studying_calc_real_analysis

azure helm
bronze owl
#

You could try analysing the movements of vertex A and B, and finding some sort of pattern in it

tranquil glade
#

in hyperbolic geometry what similarity of triangles hold

maiden brook
# azure helm

when do u first get back to the original position?

#

after how long?

azure helm
#

after 5th is rea-eated

#

if we 2007mod 5 is 2

#

cbad

bronze owl
#

It goes back to position 1 at the 5th iteration, but if you take 2007 mod 5, you would be accounting for the original position twice

obsidian harness
#

the hyperbolic law of cosines depends on the Gaussian curvature

#

so SSS doesn't apply

#

nor does AA

#

but I think SAS should still work

#

hyperbolic law of sines is strikingly similar to the regular one btw

grave pond
obsidian harness
#

ah that makes sense

#

yeah why did I mess up the SAS lol

faint pasture
#

if im given an equation of pair of straight lines

#

how can i get the two lines from it

#

(dont suggest quadratic formula- thats too damn slow)

grave pond
#

Just for clarity, you have a single quadratic equation in two variables, and you happen to know from somewhere that its solution set is the union of two lines, and you want to figure out what those lines are?

meager skiff
#

I was wondering if this is SAS?😭

sturdy stone
#

it is

meager skiff
#

Alr thanks broski

faint pasture
#

like the quadratic eqn has been formed by multiplying equations of two lines

#

and i just want the equations

sturdy stone
#

factor

faint pasture
sturdy stone
#

welp

faint pasture
#

;-; is there no decent way then?

#

quadratic formula's my only hope?

#

;-;

sturdy stone
#

you could multiply out (ax+b-y)(cx+d-y) and equate coefficients and solve the system

#

but thats definitely also slow

faint pasture
sturdy stone
#

yh exactly

faint pasture
#

;-; ah okay thanks anyways

grave pond
#

I don't think you can avoid solving at least one or two single-variable quadratics along the way ...

#

If your equation is, say, pxΒ² + qxy + yΒ² = 0, then the result is two lines crossing at the origin, whose slopes are the two solutions of mΒ²+qm+p=0.

faint pasture
grave pond
#

Okay, if solving single-variable quadratics is acceptable, then we have something to work with.

#

View your equation ryΒ² + (qx+t)y + (pxΒ²+sx+u) = 0 as a quadratic equation in y, and set its discriminant to 0. That gives you a quadratic equation in x that you can solve to find the x-coordinate of the intersection point. (This should actually be quick, since if your original equation is indeed two intersecting lines, the equation in x has a double root!)
Then plug that x in and solve for y. You already know the discriminant is 0 now, so the calculation is again simple.
To find the slopes, now you can simply ignore the terms of degree <2 -- this corresponds to switching variables to translate the intersection to the origin, but you don't need to actually do the calculuations, because they don't change the degree-2 terms, and you know the lower-degree coefficients will end up at 0.

#

And now the only full application of the quadratic formula will be finding the slopes from pxΒ²+qxy+ryΒ²=0 as above.
Then you can write down the equations of the lines in point-slope form.

faint pasture
grave pond
#

We want the x-coordinate where there is exactly one matching value for y.

trail tendon
grave pond
#

(You'll need special cases if the original yΒ² coefficient vanishes, in which case one of the lines is vertical).

faint pasture
grave pond
#

(Also, if "discriminant(x)=0" ends up having no xΒ² term, then the lines are parallel -- or else your original equation wasn't for two lines at all but for a parabola).

grave pond
#

The algebra actually works out pretty nicely, giving the intersection point
$$ (x_0, y_0) = \left( \frac{2rs-qt}{q^2-4pr}, \frac{2pt-qs}{q^2-4pr} \right) $$
and the common denominator $q^2-4pr$ is also the discriminant in the equation you need to solve for the slopes afterwards.
If it is negative, the conic was an ellipse (or a single point or nothing), and the above expression is its center.

somber coyoteBOT
#

Troposphere

grave pond
#

It the equation was a hyperbola, the very same procedure gives its asymptotes!

devout elm
#

hiii ...
how to visualise the trig functions on unit circle
(i dint get tan and cot )

devout elm
#

yha.. but why

obsidian harness
#

similar triangles

#

so for example, CBD is similar to BED for tangent

devout elm
#

yes .. but.. then what

obsidian harness
devout elm
#

k.. lemme see

obsidian harness
#

e.g does CB/BD = BE/ED work? and so on

devout elm
obsidian harness
#

(and that CB = 1 ofc)

obsidian harness
#

😭

obsidian harness
#

but that's completely unrelated to BE

#

in maths there's not always an easy answer or a 1 line reason for everything

devout elm
#

the thing i dint understand is if i make a tangent to the hypotaneus .. how can we say its sin/cos

#

the tangent if extended can also be cot

obsidian harness
#

assume you only know that CB = 1, BD = sin x, and CD = cos x

devout elm
#

if they are similar .. i can say sin / cos = DE/ sin ?

obsidian harness
#

you're almost there actually

#

cause you want to find BE which is a hypotenuse

#

So you need to be using CB from the triangle CBD

devout elm
#

uhhh .. now i confused

#

ohh got it

#

now what about cot

obsidian harness
#

sinilar, so if you call the intersection of the pink and red lines F

devout elm
#

ohh yaa got it

obsidian harness
#

triangles FBC and FAB are similar

devout elm
#

thanx a lot πŸ™‚

obsidian harness
#

yeah let me try, so sin/1 = cos/x, x = cos/sin yep

#

npnp

elfin cave
#

hey uhh, so im kinda stuck on this. tangentX=2/3 then to find the missing angle you would do Tan^-1(2/3) but then the angle would be .588. i have no clue whether im right, and im even more confused how an angle is .588 on a right triangle

lime dune
#

radians!

#

if you want it to be degrees, multiply by 180/pi

#

also there's nothing wrong with an angle of 0.588 degrees; certainly it doesn't make sense in the context of the question you're doing

#

but in general it's pefectly possible for such an angle to exist

elfin cave
#

thank you so much, that clears up everything

lime dune
#

npnp

stuck sleet
#

wouldn't this whole question is wrong because a triangle with side lengths: 3-4-5 is a right triangle?

silent plank
#

why do you think that means its wrong

upper karma
#

there is nothing wrong with it

fading basin
#

what is the best way to do the following
I have a plane
a vector on that plane, v
and integer grid on that plane
I want to find the closets integer vector to v, such that its length is less or equal to length of v

obsidian harness
#

out of all the integer vectors that have a similar length

#

so if your vector v had length 8.7, you would do 8.7^2 = 75.69

#

so you would look for all integer vectors such that x^2 + y^2 = 76 for example

fading basin
#

and this specific one -- people are saying it is easy

obsidian harness
#

if you can find the coordinates of the endpoint of vector v, just look at the four nearest vectors

fading basin
#

yea
(well, I have additional conidion that I only care about the closts vector that is shorter)

obsidian harness
#

oh true hmmmm

fading basin
#

so, what is the algo

#

where can I read about that

obsidian harness
#

IDK I'm not a CS person

fading basin
#

damn(

obsidian harness
#

it just sounded like an interesting problem

fading basin
#

and one of them is bound to be shorter?

wooden river
#

why is the answer quadrant 2?

#

also is it negative beacuse of the < symbol from the question?

trail tendon
wooden river
#

why does it say theta is in quadrant 2 though?

trail tendon
#

it says quadrant IV, look closely lol

wooden river
trail tendon
#

IV -> 4

#

stil kinda small but yeh

wooden river
#

damn okay

#

i see that now

trail tendon
#

yeh

wooden river
#

lol thanks....

trail tendon
#

they hab messy writing πŸ’€

wooden river
#

yea

#

blame my prof

faint pasture
trail tendon
#

real πŸ˜‚

faint pasture
#

puns intended

wooden river
#

so is it negative because its less than?

#

in the question\

#

negative values

dull pilot
#

how to rotate a rectangle

trail tendon
#

quadrant 4 is under the x axis, so the y values are negative so the sin is negative.
quadrant 4 is under the x axis but to the right of the y axis, so the y is negative and the x is positive, so tangent is y/x is negative/positive -> negative

wooden river
#

or is it beacuse since quadrant 4 is negative

trail tendon
#

sin is the y
cos is the x
tan is sin/cos is y/x

wide mason
#

hey i nee help in geometrey

#

Geometry*

#

if anyone knows pls dm me

#

i need help

upper karma
#

i have enrolled in geometry

#

5 minutes ago

trail tendon
#

nice

upper karma
#

i have learnt about

#

3d space

#

2d space

#

1d space

#

rays

#

segments

#

lines

trail tendon
#

oo

grave pond
# wide mason hey i nee help in geometrey

You're a lot more likely to be helped if you actually ask some questions either here or in a help channel (see #❓how-to-get-help).
People are not very likely to promise you they're going to help, when they don't even know if the particular problems you have are ones they can help with.

harsh crow
# azure helm

50 degrees because central < BOC is 100 degrees and <BAC and <BOC intercept the same arc and the inscribed angle is half the measure of the central < meaning m<BAC = 100 deg/2 = 50 degrees

azure helm
#

exactly detective L

#

but that was over a week ago

harsh crow
#

im just scrolling up lmao

harsh crow
#

because apothem = sqrt 3 so 2 times that is 2 sqrt3

#

but im not sure

azure helm
#

I got 6sqrt(3)

#

u sure?

#

maybe I did mistake

harsh crow
#

maybe i did

#

holdo n

harsh crow
#

yeah its 6 sqrt 3

azure helm
harsh crow
# wicked jetty
  • sin^2(x) cuz 1-csc^2x is the same as (sin^2(x)-1)/sin^2(x)) and doing division u get -sin^2(x)
upper karma
#

. In the convex quadrilateral ABCD given below, m (∠BCD) = 90Β°, |AB| = |AC| and AC ∩ BD = K. If the areas of triangles AKD and BCK are 10 cmΒ² and 25 cmΒ² respectively, how many cmΒ² is the area of ​​quadrilateral ABCD?

A

10 cm

D

K

2

2

25 cm

B

C

A) 55

B) 60

C) 70

D) 105

E) 90

deft drum
#

I am learning functions for limits and continuity where the instructor mentions the domain and range of function depends on its nature like what all values it can recieve and return.

Here they mention domain is set of all real numbers for the area of circle, now since they included extra information shouldn't both range and domain be both positive real numbers? Negative radius doesn't make sense to me.

If area of circle wasn't mentioned then we could have concluded domain as all real numbers.

grave pond
#

The expression pi rΒ² makes sense in itself no matter what r is. It's just only when r>0 that it is useful for finding the area of a disk.

lament shore
#

This is a GCSE maths question so it shouldn't be hard for most people here,πŸ˜… can someone help me with this?

faint pasture
# lament shore

yea soo let the distance between the bases be B
and the height of tower be X
thenn try to draw out a diagram which includes the 19 degrees angle

meager skiff
#

Anyone know how I can survive Geometry in the summer?

trail tendon
crystal tiger
tall coral
#

what makes undefined terms undefined?
Like what stops me from defining a plane as R^2