#geometry-and-trigonometry
1 messages Β· Page 62 of 1
Nah i was talking about repeteadly using sin(a+b) π it was the only real way to approximate before calc came sooo i mean yea
It is tedious but uea
ohhh π
what do you know?
Is there a better way though? Consider that calc and graphs dont exist
The other 3 are just reciprocals of these
Look into the unit circle definition
yeah
learn the other three trig functions
then look at unit circle
and memorize the values
Btw viper this
Cosecant or simply csc
XD
how do you know sin(1 deg)?
and cos(1 deg)?
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
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
Oh wait
We know sin(18)
well then ur not gonna get anywhere
yea
Boom we just have to solve a 18th degree polynomial now
We got 2k years before newtons arrival thats plenty of time xD
Extremely
i mean theres trig identities
really?
Citruz. Lmao
π
Nvm since we know sin18 we know sin 6
Since we know sin6 we know sin 2
so wait
ur assuming sin(1 deg) = 0?
Ez pz lemon squeazy
Nah i was joking about that
π
Heyy what's going on here?
Couldn't sleep so thought of checking here
we're sleeping
as you should be
Lol man sleep talking math
You're wild
Just thought of a way to calculate sin(1) give me my nobel already
sin(1) = 0, heres ur nobel prize
π
Lmaoooo it is close enough for most purposes tho xD
Can't you just call it zero like we physics people do
π
We can
But you see if we do
Then thatd mean sin3 =0
Then thatd mean sin 30 =0
Soo shit just breaks
XD
No it doesn't
Trust me
Small angle => Take the shit to radians
Calculus hasnt been invented yet
Or just say zero and move on
sin(1 degree) = pi/180
We live in 500 BC
π€―
Again calc hasnt been invented dont cheat using the taylors series
Ohh then how are we here?
The internet?
π€
did pi need taylor series?
I- oky-
It doesn't I guess
Sin(theta) = theta
Needs taylor series
I just told you-
Lemme tell you something
Pythagoras wasn't a real person π
Believe me he really wasn't
how come?
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
It was a cult that called themselves Pythagoreans and had an imaginary idol
They worshipped math
I'm not even lying
Lmao wtf
There are literal articles about this
the weird thing is we're taught math backwards ._.
Articles arent a trusted source tho
Are we?
Maan ask any historian
you think you're joking...
Or history enthusiast
but honestly not a bad idea, to an extent π€
Or conspiracy theorist
You can teach them graphs though
Really not a bad idea
yes
Tbf yea itd simplify a lot of shit
Oh is that so?
Show me a record that a person named Pythagoras existed
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
It really does and that is wild
why not teach them IBP?
its not hard π
Show me a record that the "village" or "cult" exists
Yeah don't they teach graphs and all here in 8th or 9th grade?
Its not, but its not needed at the basic level
They do?
who said anything about basic level π
I have been doing graphs since lile 2nd grade
real
But they were like simple bar graphs and shit
π why th would yoy want a 7 year old kid acting like an integral freak
That's whataboutery man
They are the foundation of all of calculus though
literally why not
Lmaooo okay dude go sleep
Id get an inferiority complex thats why xD
Like I'm serious about this lol
π
dude i feel like it doesnt even matter how old u are lol
unless ur like 3
but at a certain point your brain is good enough to be able to understand
so liike
why not
Lmaooo you are wrong though
But like you need to know multiplication of polynomials before integrating the said result
Okay then just a sec
Lmao
yeah
i dont mean skip to calculus
i just mean teach it faster π
I mean there wont be any proof
Kids struggle with the current slow curriculum wdym teach it faster- π math is one of the most difficult subject for half the kids in any gjven room
(Your ed system sucks then- we were taught algebra in 6th grade so like 10?)
We had stats and probability and shit before that
Not here
they just dont each it well or smthn idk :l
I found somewhere it was written that Pythagoras was a real person and he created that cult π
Lmaoooo i mean logical and creative thinkers are seperate
That's an year or 2 later I guess but not too late in my opinion
i feel at least for me i could have been taught things a lot faster
π
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-
Seems okay to me
Why are you guys so pissed about being taught slowly lol
I mean you are in mathcord arguing about the ed sytem so yea you are a logical thinker-
I mean all of the systems eventually throw students at the same level when it comes to university
am i though π
human, to be exact
90% of the ppl here are-
Irish human to be exacter
Check his sect now lol
I hacked youπ (you said so above lmao)
XD
guys linear alg or multivariable first
Lmao i even know your religion
π
Linear is funner imo, never tried multivariable
I guess linear algebra first is a requirement isn't it?
not at my school, thats what worries me π
so im hearing linear algebra first...
Like it gives you intuition to visualise vectors and all that
It's needed in multivariable I guess
That too
Man why are you leading him like that
Lol it's so funny xD
XD
Then you should probably learn philosophy
You might wanna kill yourself early π
Sorry what the hell did I just say
You try to go in space, i try to go below earth (earth is flat obv so i can go below it duh)
Nah earth is just a pringle
It might be a snickers bar
this user has been arrested by the fbi for using the n word without a pass
Man it literally means shorts doesn't it?
Are those rsndomly chosen too?
Naah obviously not
That's dumb
π
Do USA and China first
Aaah no man not Australia
Nagasaki
Berlin
New York π
Man what the hell lol
Perth
Canberra?
i don't know australian cities
I know like 0 australian cities
Which one is remaining then
Lmaooo
What the hell is that?
Sounds like spanish
Lawl
It's Australian and no cricket matches I've heard being played there
Doesn't even qualify as Australian
π
Lmaooo the criteria is crazt
Ulanbatar was mongolia right?
And which country was lagos in?
My man took out the most underground cities from the whole world just to confuse us π
Tbf everything except bendigo is kinda famous
Ulaan bataar is the capital iirc
Lagos was in the news a couple years ago
Still not like DC famous or Delhi famous
I guess I know why he wanna poison that
That was quick
China from Asia
Dont poison them
I meant Shanghai lol
Pls now do berlin
Berlin
Europe then
Is it done already?
I know 2 damn german cities
And its not one of them
So yea
Oh-
Lmao
Africa cape town
Wtf lmao
Nice man
Everyone deserves to die here
So that we can know if it's a simulation or not
One small sacrifice for the bigger fact
Could we perhaps try to walk the conversation back in the rough vicinity of the channel topic?
Oh fuck i forgot that sorry
hopefully not during it right
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
im not very familiar with this but they kinda look similar to square waves and functions from fourier analysis
no idea though i could be wrong in thinking theyre related
try and compute the equation for a square
u will see its just a piecewise function involving regular trig in the end
they are not very related
oh yes, I had seen these just recently and they seemed pretty similar, trying to graph them in desmos they even resulted in a graph of the corners of a square so probably the closest so far
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?
I think that may be the way to go, of all of the graphs ive seen so far this one sorta looks like it could be made with a piecewise function for the different parts
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.
For each of the sides (except horizontal one) the expression in the corresponding case becomes a segment of a scales and moved tangent function.
(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).
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.
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...
for what troposphere described you primarily need trig stuff
i did it
oh my gosh
i drew a square using c(x) (square-cosine) and s(x) (square-sine)
c(x) and s(x) are graphed too
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
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
i implore u to figure it out urself
count on it, I am really interested in learning to do it, maybe even achieving more shapes too
it should be easy to see the parts where its just 1 and -1
the parts where its not 1 and -1, draw a small triangle
work out the geometry
I think Im beginning to understand, ill keep in mind drawing out the triangle, I will experiment in desmos once im able and see
the hexagon was harder
i only made half of it
because... the rest seemed like a waste of time
the hexagon isnt rotationally symmetric by 90 degrees
which is why the "cosine" and "sine" functions dont look similar
is k = 1/60? that feels wrong ngl
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
oh wait
this isnt a sine wave
uh
yeah π
u should recognize that this is the parametric equation of a circle
and uh
well it moves a distance of 120pi every second
which means it made... 120pi/2pi = 60 revolutions in 1 second
i was just looking at the equation for y my bad
so the period is 1/60 hertz
oh so my logic still applies?
oh alr
thanks
is there a way to convert hertz to radians π
oh
wha
yes
tbh
wait i dod this wrong
the radius of the circle is 6!
so the circumference is 12pi
oh so 10 hertz
which means the distance of 120pi is only 10 revolutions
wait would i show this as 1/10
or just 10
its 10 revolutions per second
ok so just 10
so the period is 1/10
oh
ok ty
convert to radians
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
you donβt need trial and error for this, look up parametric curves to see how they did it
I think ill check into this for the moment
I will see what I can do but I do think they could be pretty helpful for these graphs
yeah it did not involve trial and error for me
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?
P0, p1 refers to points on the line?
are there not infinitely many circles tangent to any two given lines
Radius is given
Yea thats true
Lmao but its given that they are intersecting so yea
oh true
Hmmm
Well the problem is rather doable.if yk the formula for distance between point and line
perpendicular distance formula
Hmm
|ax + by + c|/sqrt(a^2+b^2)
Yea
Yes
Yeah they are finite lines but it's ok to consider it infinite as I just want to fit a circle between it
Well get the equatiom of line from there
Is there like a direct formula or should I solve the line equation? It's for programming purposes
if its finite wouldn't you have to check all 4 and see which ones have the tangent points actually on the line
surely there's an easier way
Well try it the normal way and see if you can derive the formula
Yeah that's also an issue but I was thinking if I solve it for an infinite line first I can get an idea on how to make corrections to have it on the side I want
yeah try that
Also there is one case, one if the lines is always perpendicular to X or Y axis
No?
how else do you do it
Also there should logically be 4 but the method only gave 2 so idk whats the problem
what method
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)
The circles you get both have the point on line
absolute value is on both sides so shouldn't it give 4 results
But a=b and -a=-b is the same thing
This definitely doesnt belong in this channel
Sorry again, where should i post it?
The finding equation of line then calculating distance and letting it equal to R for both the lines
Then solving the linear equations
Iam not aware of that tbh
alright, thank you anyways
oh i figured it out
if you use radius you get 4 solutions
because instead of |...| = |...| you have |...| = |...| = r
Yeah itβs 40
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
So x is just 40
I feel like I cheated though because I used sin(30) = 1/2
Add all the different angles and add to get 360
you mean the four angles of the entire quadrilateral?
cuz thats not possible because you only know 2 of the angles
wdym? there's four angles visible
you mean 50, 70, 80, 60, and ? ?
WAIT YEAH IM SO DUMB I DREW THE LINE AS WELL ππ
bruh
it just cuz i was doing it during my lunch break
i was half eating half doing it
on my phone mentally

wait
iβm so confused
π
50 + 70 + 80 + 60 = 260
360 - 260 = ? = 100
but the answer is not 100, why do you think this method ^ would work?
Anyone have any advice on this problem? I think this has to do with trig identities but im unsure what im doing wrong.
First thing I can think of is use the quadratic formula
Correct so far, now if tan x - 8 = 0 then tan x = 8
not -8
Oh also there are infinitely many solutions if your domain is the real numbers
Yeah so you need to be adding +n pi to your 2 principal solutions
just arctan them and ye
is this a construction of a median?
@obsidian harness
oh so it has to be B then, correct?
nope
those two lines are definitely not parallel
is it a perpendicular line?
yes
tyπ
yo @everyone, anybody willing to help me for my hw
Perpendicular bisector I think
actually no
basically you have one point A in the diagram, and not two points say C and D
ofc you construct the perpendicular to point A by using your compass to mark out equidistant points C and D
mhm
I have literally found everything BUT what I'm supposed to
did you use the fact that those two specific segments are equal in length to find any of these
i feel like if you remove that restriction all of this still holds
nope! I just used a bunch of angle equivelencies
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
you need to somehow use that fact
sounds like trigonometry
not everything
idek what I am doing anymore iguohfdszaOL
is the ans 30?
do you know the ans?
Here's what I got (quite a convoluted model, but it's apart of the process)
how do you get 30?
i dont know
Who said the quadrilateral is cyclic
one of the triangles has two equal angles meaning it's iscosoles
@tall coral how did you get 70 on the upper triangle?
Which one?
Oh nvm
I saw it
i dont understand the blue 70 degrees
i think its gotten from the blue 120
but idk how they got the blue 120
Me neither
I just saw the isoceless thing
yes i also dont know
I thought opposite angles of a cyclic quadrilateral add to 180
But the thing is its not neccessarily a cyclic quad
whats a cyclic quadrilateral
aah yess
oh
Since the green point can move to anywhere out of circle
opp angles make upto 180
And shit still satisfies
Vertices on a circle
a quadrilateral inscribed in a circle, where all the vertices are touching basically?
ah
Hmm
it can't, or the given information would be wrong
How?
the orange 80 degrees would change if the green point moved
It wouldnt?
this green point?
Green point as in the top right ome
No-
So how do you know thr current configuratiom leads to it being cyclic?
let me clean the model up a little with geogebra
Ill be back in a bit
oh wait I see where I went wrong
Hmm got any other leads yet?
Angle chasing is half the reason i despise geometry
Also idk if you know about that but i think i saw a theorem for this exact kind of situation where the bisector of a side is equal to the bisected lengths it was related to angles too i dont really remember its name or what it stated tho if im being honest
just more lines
if I can prove these two are equal, then the whole thing comes together nicely
no wrong angle
if I show all this is true, we're gold
you mean if you can prove that those are simlar triangles or smthn?
no
thats not what u ment
wait yes maybe
wait that wouldn't even work
i would say geometry is harder than algebra or precalc, imo π
i know like
I was being sarcastic π
you can pick "hard" problems from any one of them
i know π
but the geometry ones are most often the hard hardest
Cuz you can literally pick an IMO problem and it still is just geometry xD
π
let me start over
I'm ginving up tonight, I got nothing.
or just hear me out lets just call that problem unsolvable and move on
ezzzz
took about 5 mins with a friend
who said its a cyclid quad though
its gotta be cyclic
cuz of the equal lengths and also the right triangle
it must be cyclic
argh iseee
yeah but how did u guys realize it was a cyclic quad
i would never think of it
the two equal bases form the diameter
...because of the equal lengths?
and there is a 90 degree angle
yeah
yeah
and then it was obvious
bro I WOULD NEVER THINK OF THAT
that its cyclic

idk what to say

hi
are you the real doctor house
It kinda looks like concyclic + thereβs not really another easy way to do the problem if itβs not concyclic
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 $$(\cos^3 x - 3 \cos x \sin^2 ) + \iota (3 \cos^2 x \sin x - \sin^3 x )$$.
ΔARKγ MΓTTER
well compare the coefficient of the imaginary parts
.
Yes but there is one more correct answer
oh replace cos^2 (x) with 1-sin^2(x)
Ah using cos^x + sin^x = 1 identity
These are too hard for me to remember, I will check
hmm
give me a challenge for trig (not directly related to triangles or other geometric figures)
Thank you that really helped!
Now im still stuck on the solutions. arctan (1) is just pi/4, but arctan(8) Im not sure. My graphing calculator gives pi/2 -arctan (1/8). The question requests it be in radians so the answer will be something like (?) +pi(n), pi/4 + pi(n)
arctan 8 is not simplifiable
,w calc arctan(8)
unless you wanna give this as an answer that is
β BAC = 60 β AHD = 51
H - orthocenter
D - incenter
β ABC = ???
I got no idea how to solve it
I mean, i calculated the 120 angle at the top of bottom triangle
And 60Β° angle also
But it didnt help
sine rule
too find the length of the bisector
then cosine rule in upper triangle
Hi , I think u can find the solution easily with this figure
elaborate please
what- why
um... if X//Y, all Os=60
not neccessarily?
so right-bottom tri's angles are 40,60,80
idk
How do you get the angles to the left of the vertical line there?
Can you explain a bit more?
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.
guess I was wrong
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.
is english fine?
first use law of consines to find DB/EB
then find <ACB
then use law of cosines again to find AB
and at last use law of sines to find x
how did you prove that that was an equilateral triangle?
OHH I FORGOT ABOUT MY SPECIAL TRIANGLES
UGHHHH
hi im new to discord, can anyone help with taking pictures and sending it to the group, im also on computer
Are the angles the same?
You can use the angle bisector theorem to find this
4/3 = x/9
Same for the other triangle
Download the Discord app on your phone so you can upload pics directly
that's the easiest way
Yay
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
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
what?
b^2 + c^2 = a^2 in a right triangle just means the side with length a is the hypotenuse
still valid
aight
A,b,c are just variablrs
They can mean anything
Hey uh sorry but can you explain something to me? I have to prove that if aΓtan(A)+bΓtan(B)=(a+b)Γtan((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)
I have test tommorow and still confused on how to solve trig equations, could someone help explain a few of these review questions?
I HAD MY MATH FINAL EARLIER TODAY! IT WAS EASY, I THINK IβM GONNA END THE SEMESTER WITH AN A!!!
Oh hi, what identity are you attempting to verify?
ayyy nice π
Frrrr
what was it on?
Probability and stats and basically all of trigonometry
ayy XD
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 ππππ even tho it was just a mini unit and Iβm not even in ap stats
Canβt wait for ap calc A and pch next year
What da question
Has anyone ever done the flvs geometry 1 and 2 I am struggling hard with it if anyone could help out with it.
If you already know the lengths of all the sides, isolate the cosine function and then inverse cosine both sides
On its m<c = acos((a^2+b^2-c^2)/(2ab))
You can get that by rearranging the law of cosines, which is c^2=a^2+b^2-2abcosC
ended up rearranging it yea
Oh ok
thanks
Someone pls verify that
5sin38/sin17 = (-5tan55tan38)/(sin55(tan38-tan55))
(degrees not rads)
If it seems to be true with the calculator, actually proving it should probably start with sin(17β°)=sin(55β°-38β°) and a sum formula, followed by algebra crunching.
whatβs the meaning of the distance of non-coplanar straight linesοΌ
Any two straight lines will always be coplanar no?
?
Not in 3d space.
Nvm
If the lines are not parallel, there will be exactly one line that intersects both of them at right angles.
i'm interested in how to prove it.
The distance between those two intersections is the shortest possible distance from a point on one line to a point on the other.
I'd use coordinates, with some conveniently chosen coordinate system.
We haven't learned about spatial coordinate systems yet, can we use the synthesis method?
Undoubtedly, but I can't immediately rattle off a proof. What is the exact claim you want to prove?
βIf the lines are not parallel, there will be exactly one line that intersects both of them at right angles. βthis proposition
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
if you're just starting to study these two days before the exam
all i can say is
you should've started way earlier
ik i made a mistake but now i need help where can i study this from?
Its correct though
how?
(-0.4)^(-0.4) is defined though
why
I cant elaborate rn, ggl it youll find the way
(-5/2)^(2/5)
Hmm
So desmos has just pointed out multiple points like these its all correct
maby it just cant calculte it
,w calc tan(3)
Hm since its less than one there are gonna be infinite pairs of x and y
Sooo y not
yha .. trig funtions are weird
I think fun but okay
im rn in 9th .. so for me .. i dont understand some things
Well thats what makes it fun
If you know everything then its boring no?
very true .. my summer holidays are going on and i have target to finsh calculus
though sometimes its fun to already know \
IK
but if i go slow then ill take me 1 year to do it 
realistically if youβre still trying to wrap your head around trig funcs
im not sure youβll be able to do it in a single summer
uhhhhhhh ............
donβt rush, make sure you actually get whatβs going on before you βmove onβ
k.. ill do trig first..
any way to learn trig better ?
is there online website ?
i cureently use khan acadmy
Idk i did calc 1 and 2 in like a month combined
yea figured
noice
I need help with Stereometry. Anyone who understands this? I really need help. tomorrows a exam. :)
hello
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
π
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?
i understand how to calculate the area using both but i havent been able to figure out how to use those two to find the radius
i confused myself alot and i tried converting the central angle to degree but still came out wrong
Can you explain, with either words or formulas, how you would compute the area if given the radius and an angle in degrees?
theta/2pi * pi*r^2 = theta*r^2/2
fraction of area * total area
2 pi is 360 degrees
Great!
So if you insert the known values there, you get the equation
3 = (1/5)rΒ²/2
thank you guys so much, i finally solved it thank you!
Whoops, sorry, I confused you for Jess.
no worries, i already knew how to compute it i just have mad adhd and needed someone to help for a sec
oh, he asked the question and you were trying to help him
because you phrased it like a question i was just answering you
my bad
I must have sounded insufficiently Socratic. :-)
hI
It is a Geometry problem "Draw a plane P and then draw a line and a semi-line on it"
pls help me
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.
U gotta be more specific bro
sorry ive finished most of that its just these two problems are really confusing me
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.
studying_calc_real_analysis
any ideas?
you are asking to me?
nah, I dont have enough geometry intuition, can you guys hint me on this?
draw a diagram and draw what u want
select two of them it doesnβt matter
draw the segment that marks the distance u r looking for
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?
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)||
yes
how do I solve this ?
I tried inscribed angle theorem but didnt do the trick I think
Glad I donβt have to learn this π
OB and OA are both radii
It's an isoceles triangle
180-110-2x=0
From there it's pretty intuitive
If O is the center of the circle, anything line starting at O that touches the circle will be equal to the radius
wow
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.
studying_calc_real_analysis
You could try analysing the movements of vertex A and B, and finding some sort of pattern in it
in hyperbolic geometry what similarity of triangles hold
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
look up hyperbolic law of sines and cosines
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
Hyperbolic triangles are similar only if they're congruent.
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)
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?
I was wondering if this is SAS?π
it is
Alr thanks broski
yea
like the quadratic eqn has been formed by multiplying equations of two lines
and i just want the equations
factor
the coefficients arent setup for that to be ez unfortunately
welp
you could multiply out (ax+b-y)(cx+d-y) and equate coefficients and solve the system
but thats definitely also slow
that's worse than the quadratic formula-
yh exactly
;-; ah okay thanks anyways
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.
those are rather doable but the ones with px^2 + qxy + ry^2 + sx + ty+u =0 are too time consuming
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.
why do we set the discriminant equal to 0? it can just be a perfect square no?
We want the x-coordinate where there is exactly one matching value for y.
complete the square.... naj:kskull:
OH i seee! thank you soo much
(You'll need special cases if the original yΒ² coefficient vanishes, in which case one of the lines is vertical).
π i- try that lmao
(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).
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.
Troposphere
It the equation was a hyperbola, the very same procedure gives its asymptotes!
hiii ...
how to visualise the trig functions on unit circle
(i dint get tan and cot )
yha.. but why
yes .. but.. then what
you'll honestly learn more if you try it out by yourself
k.. lemme see
e.g does CB/BD = BE/ED work? and so on
it works as it is similar
I mean if you only know that CD = cos x and BD = sin x, can that tell you that BE = tan x?
(and that CB = 1 ofc)
yes becouse it is slope
π
okay yes tan = sin/cos is the slope, so the slope of line BC yes
but that's completely unrelated to BE
in maths there's not always an easy answer or a 1 line reason for everything
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
so as before, you can show that BE = tan x using similar triangles CBD and BED
assume you only know that CB = 1, BD = sin x, and CD = cos x
if they are similar .. i can say sin / cos = DE/ sin ?
yes!
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
sinilar, so if you call the intersection of the pink and red lines F
ohh yaa got it
triangles FBC and FAB are similar
thanx a lot π
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
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
thank you so much, that clears up everything
npnp
wouldn't this whole question is wrong because a triangle with side lengths: 3-4-5 is a right triangle?
why do you think that means its wrong
there is nothing wrong with it
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
depends on what you mean by 'closest', but one approach is by cosine similarity where you aim to maximise the dot product
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
I think it is called CVP or something
clostest vector problem
I can see ppl discussing it for arbitraty lattices -- but this is where it gets hard
I only need it in 2d for integer lattice
and this specific one -- people are saying it is easy
ah 2D is nice
if you can find the coordinates of the endpoint of vector v, just look at the four nearest vectors
yea
(well, I have additional conidion that I only care about the closts vector that is shorter)
oh true hmmmm
IDK I'm not a CS person
damn(
it just sounded like an interesting problem
oh
actually tho
this is just rounds up and down, correct?
and one of them is bound to be shorter?
why is the answer quadrant 2?
also is it negative beacuse of the < symbol from the question?
it's in quadrant four
why does it say theta is in quadrant 2 though?
it says quadrant IV, look closely lol
yeh
lol thanks....
they hab messy writing π
thats a W
real π
puns intended
how to rotate a rectangle
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
or is it beacuse since quadrant 4 is negative
for quadrant 4, the y values are negative and the x values are positive
sin is the y
cos is the x
tan is sin/cos is y/x
nice
oo
You're a lot more likely to be helped if you actually ask some questions either here or in a help channel (see #βhow-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.
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
im just scrolling up lmao
also i think this one is 2 sqrt 3
because apothem = sqrt 3 so 2 times that is 2 sqrt3
but im not sure

i got sqrt 30 im not sure tho
- 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)
. In the convex quadrilateral ABCD given below, m (β BCD) = 90Β°, |AB| = |AC| and AC β© BD = K. If the areas of triangles AKD and BCK are 10 cmΒ² and 25 cmΒ² respectively, how many cmΒ² is the area of ββquadrilateral ABCD?
A
10 cm
D
K
2
2
25 cm
B
C
A) 55
B) 60
C) 70
D) 105
E) 90
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.
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.
This is a GCSE maths question so it shouldn't be hard for most people here,π can someone help me with this?
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
Anyone know how I can survive Geometry in the summer?
start working on it rn
are you taking a Mr D course
what makes undefined terms undefined?
Like what stops me from defining a plane as R^2

