#geometry-and-trigonometry
1 messages Β· Page 114 of 1

Exactly!
i really love geometry, i just proved to myself what the missing side length of a rectangle has to be to fit a rectangle with a perimeter of 16 units based off of the information that one of its sides is 3 units wide.
That same logic can be applied to anything and everything, an angle for two lines can't exceed 180 degrees because of the underlying definitions. You can deduce things and induce things using knowledge that you know and don't know.
Maybe I'm just late to the party but does everyone see it like that? That picture applies to many other aspects outside of math/just-drawing-stuff on graphs
i feel like i got reincarnated as aristotle by learning what i know so far in school
Some people can do it better than others
mhm
this is so much fun!!! this is just like a puzzle
I don't understand why the long line in a triangle for example has a decimal/fraction for it's length, intuitively wouldn't it be a whole positive integer?
Would it have a whole length?
i mean whole integer
Yeah, would it?
Hm
What if you rotated it to be in line with one of the other sides?
well take a wall for example and a ground, if you want to calculate the length of something leaning on it then it would be like duplicating the wall or the ground and rotating it in a direction
it has to be longer than both individual sides
because otherwise it won't connect both points
Right. Who's to say its length should be an integer though?
This is the idea of the pythagorean theorem
$a^2+b^2=c^2$
pebble
nobody i just mean intuitively it's a bit odd if you don't think about it and randomly see it and then you ask (Why is it a fraction/etc?)
Yeah, I get that.
Well the pythagorean theorem only matters so long as we can use it right? so long as we have constructions such as lines and coorinate planes right? i mean not necessarily the latter but maybe you get what i mean?
I mean, you can calculate the distance between any two points using it as well
i suppose my relevance to that is that you're bringing the Pythagorean theorem into discussion but what if you didn't already know it?
Mhm
Yea! but i think that's a property of math rather than um
I can see how it would be a little confusing, in which case, it's time to learn it!
im not sure
I've learned it before and i know it and i've used it but, i think as with many other formulas it's better to get an idea or grasp on the whats and whys first
before you generalize something
right?
I generally agree with that. That's what I always try to do with physics. Getting an intuitive understanding of what you're doing and why you're doing it and why it works helps you better understand and solve new problems.
In that way, it's less formulaic and more logical
i suppose an analogy to this is that you're telling me what f(10) in a formula is, but generally you start with the first integers of a function and expand from that/generalize
Absolutely
i watched a video of a math teacher explaining that if you think calculus is just formulas then you don't know calculus
as in calculus is the study of something specific
rather than just a bunch of operations abstractly
Yeah, I think calculus is a good example. You can understand the definition of a derivative, you can learn the formulas for differentiation, and then you can learn integration, but if you don't understand what those operations represent, it's no good, you can't apply it to anything. That's another thing I like about physics, it takes these ideas and applies them directly to the real world in ways that make it clear what calculus is useful for.
If we label these coordinates as A, B, and C respectively, then we can devise properties about these vertices and the whole shape through the tools that we've built before
Yep
Yea
That triangle specifically is special though because it's a right triangle.
I suppose any triangle is special then, because the angles stay the same no matter what in math, i mean 90 degrees isn't the same as 110 for example of course but a triangle with a certain degree still has properties such as adding up to a certain degree right?
I mean, in Euclidean geometry with shapes that have straight lines, all triangles will have angles that add up to 180 degrees, sure. You can have a right triangle with one of those angles being 90 degrees, you can also have other triangles where that's not the case, in which you can always break the triangle that's not a right triangle into two smaller right triangles by constructing a line perpendicular to one of the bases and having it intersect the opposite vertex.
i'm feeling way more comfortable with the coordinate plane and points on the plane and what happens to them now that i'm learning geometry, because before it was scary and i didn't know a ton of these properties that i'm learning in geometry such as rules of lines maybe
Lol ,yea
Just wait until you get to trig, that's fun
But anyway, what makes a right triangle special is that the basic trigonometric functions apply to them nicely
Yesss, but i suppose that in the same vain trigonometry is just geometry but one that deals with "tri" or triangles, so 3 angles.
Yeah
i think i understand a bit
Yeah... in situations like this it doesn't hurt to have a white board, lol
Yea that's what i meant, so i think "anything" can be special because yes it would be "nicer" for trigonometry and stuff, instead of having to make like 14000 different stuff that you have to memorize
so it's definitely special in the case of studying trig and implementing it
but in general, angles probably don't care about what you call the shape right?
Yea it's just i haven't seen lots of those words in action before
i suppose that the study of geometry is the properties that this has when we for example add another line etc or close an object
because we start with certain premises or axioms, in euclidean geometry. Correct?
Yup
yea
And then if you do spherical or hyperbolic geometry you change those a bit to get different behaviors
Veritasium makes a good video on that
ooo
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Yup
omg i remember i didn't understand a lot of geometry, but now i'm doing some geometry in general
I mean, you probably should get through a bit more euclidean geometry before you worry about noneuclidean geometry, lol
Yea
in higher level math euclid's axioms are replaced right?
with high level math logic?
ZF and ZFC
I'm not entirely sure. From what I gather, the axiom that says that lines can only have parallel line is changed to where lines can either have no parallel lines, or multiple parallel lines.
no i mean as a whole
in mathematical analysis
In set theory, ZermeloβFraenkel set theory, named after mathematicians Ernst Zermelo and Abraham Fraenkel, is an axiomatic system that was proposed in the early twentieth century in order to formulate a theory of sets free of paradoxes such as Russell's paradox. Today, ZermeloβFraenkel set theory, with the historically controversial axiom o...
maybe this?
Maybe?
I haven't learned any of that yet, lol
Mathematical analysis from what I understand is more deriving formulas rather than just memorizing
my friend told me it's like useless to for anyone other than someone like specifically studying this or something that needs it
i can't wait to reinvent the wheel for so many formulas!
it's like a puzzle
no, it is a puzzle!
Lol. It's fun to do
Fair enough
Yes! it stimulates my brain so much!
I will say, it's even funner to do when you're finding formulas that nobody has found before on the front lines of math and physics
That can take a while
and what if you reach dead ends
I mean, you're bound to realistically, even way before your journey to discover something new
But road blocks haven't stopped society as a whole from developing new things, new ideas
i sometimes forget formulas for algebra and i'm at a bit of a dead end, but then i can just remember them or find a new path
in algebra, multiple paths lead to the same solution, and one answer has multiple paths that can be taken to achieve it
or i can ask those more knowledgable than me for help, etc
Yeah. There's always dead ends that you will come across, but that's what makes it a challenge. I imagine what people like Einstein and Shrodinger had to go through when they made breakthroughs in their field. Up until them, our standard physical model of the universe only described some things with good accuracy, not all things with perfect accuracy. Will we ever get to that point? I don't know
People like these spend years studying something specific, sure they did this over 80 years ago, but they spent each day thinking about the same thing rather than in 1 second simply find and formulate a solution because they wished to
yep
it doesn't matter whether i wish to find a solution to a simple quadratic equation, it exists whether or not i like it, and i have to respect its properties to find it, so i have to actually do work and thinking
i suppose this could maybe be generalized even further, such as if i'm a mathematician and i want to discover something new
Yeah, I mean, geometry, algebra, calculus, linear algebra, these are just tools for these problems. That's how I like to imagine it
Precisely
i was talking with my brother today, and he told me about how in his time when he was learning geometry and trig it wasn't as easy as now because he's revisited them and seen why for example the identities work and why they were created
i believe that's the only way to master something, it's to essentially discover it for yourself
seeing why it works
knowing what happens when you change something, etc
Yeah, that's a good way to look at it. That's why I said desmos would be really good to learn from because it forces you to just play around and see how things work yourself
Precisely!
See how different variables change things
Yes
I mean, I think that if you can teach yourself things, you'll probably know them better than if you only learned from someone else. I'm not saying you shouldn't learn from other people, in fact, people are a great resource! I think you should find ways to do both. That's what I do in physics. If in class we learn something from our teacher that I don't fully get, I take it upon myself to figure it out. That's what works for me, and I think I probably have a better intuition for things than most kids in my class, which shows on my test scores, yada yada.
It's doing both that gets you to heights that people back then with no resources and were pioneers could only dream of
not replaced, Euclid's axioms are for geometry and geometric consructions. ZF axioms are for set theory
Ahhhh
Thank you, i see
That's mind blowing to me
it's so hard for me to reinvent the wheel, but if i get tools from teachers and tutors then i can have a better understanding of formulas etc
i'm not a genius in every subject, nor was someone like Euclid
Yeah, it's definitely more difficult to discover things yourself, but when you think about it, that's all that matters. Soo, yea
I mean
I guess discovering new things and applying what we already know to things like engineering, what not
Yea
i want to cry so bad, because geometry is the most beautiful thing ever to me. it doesn't simply just exist in pen and paper, but it's all around us if you think about it
and i don't just mean houses and cities, but trees too, and stars
it's really symmetric
Math is all around us, always
Yea!
...
im sorry
Sometimes I feel that way too, lol.
i've spent all of my aware life (since i started thinking) viewing objects and symmetries
the neurons in my brain abstracted and quantized things around me into variables and sets
There are so many types of trees for example, but they're all under the set "tree"
i feel like i'm a reincarnate of philosophers of the past. i feel like when i'm not in the earth anymore that my legacy will still persist, that people will still try to figure out things
Yep
is this essentially math
There will always be that human curiosity
I think the reasoning you need to do math is very structured like how you're describing. I think reasoning like that helps with things other than math too, like programming, engineering, etc, which aren't all just math subjects, but, they're related
Yes
I really advise this article that i recently found, it's like a metapsychologist wrote it https://www.britannica.com/topic/thought/Creative-thinking
i dont agree with everything in it personally, but it's so interesting to think (wow) that my thoughts (ironically) are in some way supressed actions/behavior
when you think in your head, you suppress your tongue a bit from talking because you don't want to verbally talk
I'll check it out
i think this is a bit relevant to geometry in that we think a ton, and so we problem solve, we try to figure out new approaches based on stuff that we've already seen
does that ring any bells /genq
Yeah, that about summarizes things. At least in my own experiences, I find that my solutions seem inspired by what I already know, which is sometimes good, sometimes it worries me because sometimes solutions demand completely different perspectives, and those take time to come up with.
Someone like me doesn't always mind that though. Although some people prefer not to think, I despise those kinds of people (even though i'm usually very lazy) those people are not lazy but just refuse to think
Lol, I know what you mean
Yea, do you think geometry has a ton to do with problem solving in general?
I think it depends on the kinds of problems you're doing and the type of experience you have in geometry
i see, so then would you say something like just applying a formula that you already know be less problem solving and more just time?
But if you're trying to invent something from scratch logically, then that's as problem solving as it gets?
Maybe?
If you know little to no geometry and you're doing geometry, even simple problems, there's lots of problem solving to be done. If you know lots of geometry and you're doing simple problems, there's probably not as much problem solving being done. If you know lots of geometry and you're doing difficult problems, then there's plenty of problem solving to be done. As for whether I think applying a formula that you already know, I think that depends as well on the complexities of the specific problem you're trying to solve.
Yes
Yea!!!!
Honestly yea, it just depends.
Some formulas are just plug and play while others still require like doing a lot of algebra for example, right?
Yeah. But sometimes it is good to practice and play around with formulas you already know, especially if you have ideas you want to try with them
Well, I don't know if I would describe it like that. It's not like math is discovered, it's created
Even on an individual level, probably nobody knows everything about math right?
Yea
i believe it's both. in some really vague sense π€·ββοΈ
Maybe. In the context of physics, I think it's a better perspective to have that mathematics is a tool used for modeling the universe. Our models aren't perfect, they're just theories that experiments seem to align with, and they can be improved. Whether it's discovered or created, well in this context, I would say it's more accurate to say that math is created for the purpose of creating better and better models.
I mean
however you want to look at it I suppose
But either way, with our axioms there's still a lot of properties that we don't know the solutions to right? maybe like complicated things that we only have approximations for possibly?
Sure
Yeah, like the Riemann hypothesis, lol
Interesting
Nobody has proven the Riemann hypothesis, in a sense we don't know 'the solution' to it
Right
This is the most interesting stuff ever though
do you love geometry
since you practiced in desmos too
I would say I love geometry, yea
Nice!
It is very interesting, lol
idk why but i used to draw random shapes in my art notebook, i don't mean random shapes but like for example a pentagon with circle tiling's inside of it, and a circle with pentagon tiling's inside of it etc, and colored them
Since i was really young i was interested in shapes!
i suppose because it's easier than just randomly being able to draw whatever you want perfectly
Like if you want to draw a tree as perfect as possible from one angle
But a tree can be seen from multiple vantage points
Sounds like fractals
When i was a bit older, i started drawing those
Like infinite triangles, infinite pentagons stacked inside of each other, etc etc
it's the coolest thing ever to me!
that one is terrifying to me, the black areas
i'm scared of darkness and voids, that's my biggest fear
But the colorful areas that show amazing geometry is the coolest thing ever!
Hm, well unlucky for you most of the universe is just a dark void full of ionizing radiation
The mandelbrot fractal is in the complex plane correct?
Does that mean it's in 4d?
Yeah but the thing is that's only because it's dark to our eyes, in reality it's the most beautiful thing ever, minus black holes
black holes are the scariest things ever
light doesn't enter them from our perspective
No
Can you render the mandelbrot set in 3d and travel in it with a 3d camera?
oo
Yep, that's relativity
Maybe, I haven't looked into it
What do you think is at the other end?
that'd be so cool!!!!! it'd be so nice to the eyes!
It's probably just a super dense ball of neutrons to be honest
Makes sense!
I'm not really sure what would happen to matter if it's that dense
Another universe?
big bang?
No idea
black holes have a really long lifespan right?
I mean, relative to what?
to the time axis?
I think if you compare relative to other types of stars, yea
when values explode in the complex plane, is that like a big bang?
What do you mean by explode in the complex plane?
The complex plane is just one that is perpendicular to the positive and negative number line
help π
how is this not just 3d
i did
there's a million dollar check to the person who solves it
I think they define like 3 different imaginary numbers that are all kind of perpendicular to each other
bro answer my question so i can leave you
In that regard, you can make it as many dimensions as you want
hurry
What is this for the SAT? lol
ughh I haven't solved a problem like that since I was in geometry
Let me sketch it out
That's insane!!!! π€―
Come on it's not that hard, GM and GN are of length that's equal to the radius
I could be wrong, I haven't really looked into it much
I just know things like Quaternions use multiple imaginary numbers
But it's still probably something like that even if that's not correct
yeah
on gang you're no help
the help channels are really good!
you can try one too
this is the geometry and trig channel and you guys are over here talking abt your love for geometry i dont get it
i get help there all the time
I'm thinking, lmao
forget i even asked someone my age got it in 2 seconds
i LOVE geometry
with all due respect
You're really mean
So rude
you're really nice!
im not i said with all due respect
Meh
see im respectful
mhm mhm...
bro take this to the dms
You have the radius, you have the perimeter, you can solve for the distance between M and H, and since angle GMH is 90 degrees, you can just use pythagoreans theorem, right?
I haven't done geometry before and I can probably solve this if i tried. are you too stupid to solve this yourself?
What use is bickering with your fingertips if you can't even solve a simple SAT question
Haha
You have access to the internet yet you can't solve this.
and on top of that you are rude to others
You're pathetic
my heart rate is really high
degrees has nothing to do with this
bro what
How old are you?
What are you talking about?
why are you talking look at your bio π chronically online ahh
67
90 degrees has nothing to do with this because the rectangle is inscribed into the circle
So insolent
you would do patheogrean theorm and do 168+168 which is 336 i forgot the whole number subtract that from 3368 (something like that) and you would square both (adding them of course) and then square root then the answer is 1768
took bro a while to google the word
you couldn't google this?
what
That's what I did
lol
Anyway
you just used keywords "distance" "radius" 90 degrees which you said it was which it is
nt
What?
saying its 90 degrees would make it an isolesce triangle and its not
the next time you look at a mirror, remember what you are, okay?
even if u cut the rectangle
.
First of all, draw a picture of the situation and lets see if we agree
im quite fond of myself
Because you said the quad is inside the circle, I'm saying it's not entirely inside
i gave u the steps to my own question bros cooked ππ
i wouldn't have guessed, now do that alone.
its A RECTANGLE
I already got the right answer, what?
You are a disgrace
No it's not LOL
???
Please ignore them @wanton yacht
Are we real?
Clearly
Anyways
I was going to say, yeah, I think we just define i, j, and k as all between positive and negative 1, they're just all perpendicular to each other
its ok continue talking to an underage girl
That's how quaternions work
you can't insult someone and expect them to help you
you have eyesight but for how long?
how long can you have pupils for?
ok
bye
π
You get used to it
i hope i wnt have to interact with someone like that agian
thats insane
so disrespectful at the start
insane
Yeah, I mean, this world's full of people like that soo
Good luck
But that was a fun little math problem
Yea!
I remember struggling with problems like that when I took geometry, but I solved it really easily
outside of their bickering, it was nice
it's so beautiful the symmetry of problem solving
Nice!!
In physics you have to do a lot of vectors and lines and trigonometry
Technically yes, but I'm not sure if you would learn them in a geometry class.
i see
You more learn them in a physics class, or like a linear algebra class
mhm
A vector is just a coordinate though
from the origin?
Well, it could be, but usually we write them as being relative to another point
Yea
thats insane
I mean, think about it, they have a position, that's clearly a coordinate in space. Then they might have a velocity which a vector representing how their position might change over a given unit in time, which is also a vector, then you have acceleration which represents how velocity changes over time, (how much they speed up or slow down.)
Yep, you can describe all of that with that sort of stuff
trajectories too?
whats the relation between physics and geometry
It's hard to explain, it's kind of something you have to see for your self through examples. Most physics problems involve trigonometry because you have to consider like, just the x coordinate of a vector or something, and if you only have a magnitude and an angle, you need trigonometery for that
i see!
But then there's geometry in calculating things like moment of inertia, you need sometimes the areas or volumes or different objects, things like that
But I mean, there's multiple different ways to write the same problem. For example, this COULD be explained using vectors, forces, velocities, etc, but it could also be explained using relativity and curved spacetime.
And it could also be explained using energy and lagrangian mechanics which is completely different than newtonian mechanics
I mean, it solves the same thing, but it does it using energy instead of forces
and how about just a 2d graph and an ellipse?
Yeah,
ooo
If I recall correctly, showing that the trajectory for a planet around its orbit to be elliptical is actually pretty difficult though
did euclid have a z axis back then? for pyramids and cubes?
He probably considered it
i see
did he know that pyramids existed?
the 3d pyramid
Are you talking about like a geometric pyramid?
I mean, I suppose he might have considered them
Maybe. I'm not sure
Uhh, I mean we've talked about how to do like vector calculations for vectors that have higher dimensions than 2d, and it comes up when you're doing things like cross product in physics, but it mostly shows up in Calculus 3 and beyond
Lots of applied math in AI and what not involves many more dimensions than just 3 though
Wow
is that harder
No
The jump from 2d to 3d just adds one more coordinate component. The jump from 3d to 1000d just adds more and more components, but all the math is the same.
Yep
this is so insane
Yep
does gravity work like this
Shoot for the moon land among the stars
exactly
I had that same thought when I learned that quote
Tysm for talking with me!!!!!!
shoot for aristotle become better than him in reality
Ty!
π
Good luck
Yep, maybe that's part of the plan
im gonna try to master this, this is the foundations of geometry right?
It's definitely an important part of it, yea
cool!
i'll be sure to pay attention
Probably a good idea, lol
heblooo
hii
Can I ask for help with this task here
In the future, please show what you've done so far when asking for help. It gives us more context and saves time. \ \
As a hint, think of the ntersecting chords theorem. If you extend $OE$ to meet the circle at $P$ and $Q$ (where $P$ is closer to $E$ than $Q$), then what are the lengths of $EP$ and $EQ$ in terms of the radius?
Civil Service Pigeon
If you continue to be unhelpful/obstinate I will just 
RIP. π
I try to be nice and just warn the troll instead of banning them smh
It's aight man you're just doing your job...
No, you cannot in fact ping 300,000 people.
For part a, I think we can both agree that if we had the point that the cable was going to attach to, specifically on the sloped ground, it would be a simple distance formula calculation to get the total cable length, right?
Yes, but does what I've said make sense to you though?
That still won't let you ping everyone ...
Alright, so the question now is, how do we find that point?
Do you agree this is what we've got?
And then like, you've got the point where the cable attaches which is at the top of the tower
So if I was just like, alright, lets say that T = (0,650 ft) for simplicity, and I said that the point at the base of the tower was (0,0), if we can find P, we can use distance formula between P and T to get the length of the cable.
So how do we find P? Any ideas?
What did you get for a final answer?
I got a different answer for part a
What exactly did you do?
Well, that triangle isn't a right triangle though
I mean
You wrote it had a 90 degree angle in your diagram
What am I looking at?
That's right, sure, but how does that help you find the point where the cable attaches?
I like my diagram better
That's not possible
Or actually
I mean, that's not the answer I got
Does it say that's the right or wrong answer when you type it in?
Is this a test?
So am I helping you cheat right now?
Alright
Is it an assignment you can ask for help with?
.
I mean, I'll just say that from my diagram, tan(10deg) = y/100ft, so the y coordinate for p is 100*tan(10deg), and if you then do the distance formula between (0,650ft) and (100,100tan(10deg)), you get a different answer than what you said
hello
Vrochacho just search it up π₯Ή
divide this man by 0
Alr
multiply him by i πβοΈ
I think I could do better but this is what I have rn βοΈ
btw
The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.
My bad
need help
Question and its solution
Now how I'm supposed to do questions like this which require simple but not very obvious trickery.
||I'll certainly not even get to the first step of writing 1 = sin^2 A + cos^2 A||
I agree that method is a bit artificial
let $u = \sin^2 \alpha$ (cause we can find $\csc^6, \sec^6$ in terms of $u$)
we have $10u^2 + 15(1 - u)^2 = 6 \implies u =\frac{3}{5}$
so we just need the value of $\frac{27}{u^3} + \frac{8}{(1 - u)^3}$
south
ping
So there is a circle radius 6, inside contain 4 quarters of a circle also radius 6 spaced evenly. Center of the outside circle lies upon all 4 circumferences of those circles. Find the shaded area
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
If you have no other ideas, a very natural place to start would be to define an appropriate coordinate system and start figuring out coordinates for some of the relevant points.
While you do that, you can also start thinking about which tools you have that could be used to calculate the areas on one of the shaded regions.
(My first instinct would be integration, but you probably don't have that available when you're asking here. Perhaps you have some formulas for the area of circular segments, so you can divide each of the red "fan blades" into a triangle and two segments?)
I do have access to integration actually, but I kinda hate making all the equations
I think a found a way
oh wait, that isn't 3
Okay ig I would just use integration atp, it seems more complicated using only geo
Yippe
I think my first approach would be that ABC, AEG, DFG are all half-segments which I could derive a formula for; then
ABD = ABC + AEG - CDEF - DFG.
(Whoops, sorry for using different letters).
Oh I was doing that then it seem to be required finding a lot of others areas to derive to those 4
Well, whatever works for you -- I'm not claiming any particular superiority of my dissection.
Thanks for the help π©΅
Notably, red area is necessarily equal to the white area
Seems like a nasty problem either way tbh
Okay thanks. Itβs just that my way of solving was totally wrong since I mixed up some theorems
https://www.youtube.com/watch?v=-Gmw_DjgyYw
if anyone wants to try (or watch)
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could anyone help me w/ trigonometry, I don't really get it, even the basics
which concept?
do you know about circles and right triangles?
each one builds on one another, so you can take the last lesson and think in terms of its relevance in the next one
Hi guys got a quick question
Which topic should I start when I'm relearning analytic geometry
In the triangle ABC where AB=4, AC=5, and cos(β BAC)=1, as shown in the figure, point D divides segment BC in the ratio 1:2. Let E be the point other than A where the line AD meets the circumcircle of triangle ABC. When the foot of the perpendicular from point D to segment CE is F, the length of segment FC is p/qβ11. Find the value of p+q. (Here, p and q are coprime natural numbers.) PLS HELP
Tysm! I havenβt learned trigonometry but this was a really fun video!
no worries!
most of it is actually just coordinate geometry though
I see! Thanks
idea behind the approach (spoilers!):
||take the intersection point to be the origin; you have three points that lie on the circumference of a circle, so the standard approach is that the two perpendicular bisectors intersect at the centre, then the radius is just the distance formula||
I thought maybe you could transpose the angle and line somehow by like shifting it until itβs equivalent to the center, and then doing calculations
||But how can you know if the circle still has the same radius?||
there's a unique circle that passes through any 3 points (that don't lie on the same line)
by taking the intersection point as the origin, you're only translating the circle, not enlarging it or anything else
that doesn't work without finding the new lengths
I see, so it has to specifically have 3 points on the radius of the original circle for this to work?
3 points make a circle passing through them
there's no "original circle"
Interesting, what prerequisites would I need to solve similar questions? Iβm only beginning in geometry right now
you need to go through algebra 1 material
do you know how to plot points on the coordinate plane?
Yep Iβve finished algebra 1
Is that enough?
I just donβt know like the theorems and stuff like that, I believe
cool, then I think it's about developing the geometric intuition to connect algebra and geometry
Okay thanks! I recently figured that a rectangle with missing bottom coordinates with a given area can be figured out algebraically, itβs so beautiful to implement what I learned so far in math into geometry
https://www.youtube.com/watch?v=G6C0lbELl2Y&list=PLg2tfDG3Ww4s6Bjp17m9xjv4AIDX0xK3b
this might be new to you, but the algebra should be straightforward
Ty! Iβll definitely watch it
there's a whole part of coordinate geometry just on circles
I see
the tangent is always perpendicular to the radius
what else, the perpendicular bisector of any chord always passes through the origin
these are results from geometry
Does that deal with infitisimals? Or is that just logic
but how you find those lines is through algebra, of course
Nevermind I see it in my head right now, that makes sense
you're splitting this vertical line into two equal halves, so each angle is 180/2 = 90
A ray that points in a direction from the origin of a circle has a perpendicular line to it at the vertice of the thing
Yep!
I was trying to see it from the 45 degree angle
So I was wondering how would you know that
lol
Haha
Whatβs a bisector and chord?
Makes sense
@long geyser which class ?
bisector - a line that cuts an angle / another line into two equal halves
I just finished 9th grade algebra 1
chord - a line that connects two points on a circle
yeah so you'd be doing geometry next semester or what?
I see!
Isnβt that just the diameter or would that be any 2 points on the circle at all?
Yep!
You have whole circles or just basic
any 2 points
Okay
a chord is the line segment
Whatβs a line segment
the infinite line is called a secant
Iβm not sure
a segment of a line
basically a line that starts from point A to point B and stops
The one that points towards the x axis?
no
You have tangents in syllabus?
No I havenβt taken geometry in school yet
Ah
This is a weird system for me
π
For the notation of the ray do you have to always point the arrow to the right?
mhm
Two rays form and angle
You must be knowing this
πππ
Beware when you will have to use triangles and circle together
I believe you mean two connected rays, because it is not necessary that they make an angle right?
Yes my mistake
Iβm just referring to the notation like for example writing AB and then a line over it because Iβve seen that before but I wasnβt sure when to use it etc
How about disconnected rays? Can you still trace an angle between them?
And for example parallel lines?
It's used
But most of the times in question you need not to mention
I see, so you can just write AB and itβs okay?
You can measure
But you will have to extend the original
Yes but it depends ask your teacher first
Ah I understand
Okay thanks so much!
Iβm new to this
In between parallel lines
Angle is always 180Β°
How about when they are placed on top of each other
0?
I think you should first look at
Postulates and axioms of Euclid they will be used everywhere
Yes
And they are called
Co-incident lines
I saw them on Veritasiums channel if you know him
Yes it was in my syllabus in 9th π
I see
Your teacher made you watch him?
Or the axioms?
No it was part of a chapter
Ah
Transformations of points on Khan Academy, definitions of a circle line etc and how to find the coordinates
Iβm going to learn the axioms soon
π€―
Are you in 9th for sure?
I think I studied these in 6-7th π
Yeah theyβre prerequisites for geometry but Iβm not good with them
So I need to learn them again
I m in 10th
Just send me the question if you want help
I m good in geometry π
Thank you! π
Thatβs really nice of you
No problem
Thatβs really intuitive, I was wondering why in the other video the person used the x-x0 and all of that and it makes sense now!
is this a good place to talk about graphs
try #precalculus
how can I start precalculus or What do I need to know to start studying precalculus ??
Aren't quadeladeralls the same on both sides
parallel on both sides, doesn't have to be the same side size
oh
- practice on Khan Academy
- https://www.hood.edu/sites/default/files/A Quick Algebra Review.pdf
you should be familiar with all of the material in this document to proceed
I know there are harder concepts in geometry / alg 1 / alg 2 so that document really has the barebone essentials
oh yeah, IXL is pretty decent too: https://www.ixl.com/math/precalculus
Khan Academy is brilliant, i'm going through geometry and it's all very digestible
is this in algebra 2?
yes
omg i think i took this in iraq, it wasn't easy
i took that in 9th grade, i think the curriculum in the middle east is advanced
uh what do you mean by concept?
Somebody plz check my answer.
how can i find the eccentricity of this ellipse (F is the focal point) based on the given parameters ? (aka like a formula for e)
https://www.desmos.com/calculator/ektc6odc06
I've used technology to do all this algebra and you have $n = \frac{e \cos t - 1}{e \cos t + 1}$
south
rearrange this to solve for e
well my t is not the same as your theta (t = pi - theta), but you should be able to work it out
I doubt this is possible synthetically
alright thanks!
no worries!
Can yall explain to me why cos(-ΞΈ)=cosΞΈ, and sin(-ΞΈ)=-sinΞΈ I still can't understand
u know that cosine is an even function and sine is an odd one right
with respect to the y-axis
so cosine of a negative angle is the same as cosine of a positive angle
due to it being symmetric (even)
but sine is not symmetric and we cannot say the sin(-x) looks the same as sin(x)
Wait, but on the Unit circle, lets say the triangle is 30Β° and the other triangle 210Β°, we see that the triangles are opposite of each other and flipped over the x and y axis, sine would be (1/2) in the 30Β° triangle and sine in the 210Β° triangle would be (-1/2) they are not equal as due to the identity sin(-ΞΈ)=-sin(ΞΈ)
yes
if u want an explanation using the unit circle i think thatll be more understandable
so theta moves anticlockwise if its positive, and clockwise when its negative, right?
Yeah
right and we know cosine correlates to the x-axis, and sine for the y-axis right?
so imagine terminal going clockwise (-x)
cosines value is still positive here (positive x)
but sine changes since its dipping down (y axis)
Ohh, wait so we are talking about the 4th quadrant, the cosine is going in the negative direction, but still is positive, and sine goes down, so its negative
yes we are in the 4th quadrant
but if we dip into the 3rd quadrant as in the terminal keeps going, we hit the negative x-axis, so both our cosine and sine values will be negative
and when you continue in this clockwise direction, youll end up in 2nd quadrant where our cosine and sine values will be..?
Cosine is negative and sine is positive
yup
And so this why the cosine function starts at one and descends in both sides until negative in the y-axis when it goes down
By that i mean y-relative on the both sides of the x-axis, so -x and x, y descends equally until it reached its point where it becomes negative and keeps going down until it reaches its point where it can go back up
π€ i think i am just not understanding this
could u perhaps do a small drawing of what u mean
Yeah, I have the paper right in front of me
or if someone else whose understood could verify what u said lol
Alr, so we have the cosine function, at 1 on both side of "x" which is negative and positive, y dipps down equally until it reaches zero there, because as you said before when the focus line goes down x is still positive and y is negative.
Wait, but how can we represent "-x" or positive x now? Its always negative
And on the positive side, y is getting bigger and x is getting smaller because its going counterclockwise, how is y getting smaller on the function?
if i try explain further i might mess up what you have understood, i think its best i leave someone else to explain this
trig is not my forte either sorry bro π
Its really hard to actually understand, I can feel the toughness
when you have the graphical intuition it all clicks
its tough but it all is tied together and there isnt anything that cannot be explained
Can't you just mark all the intersections and use series/ parallel resistance formulae to solve for equivalent resistances between them?
Yeah, that's what I find all the time, going from basics to creating your own things, you have to think of like every single possibility that the functions can be used for
I don't think I learned how to do this
https://youtu.be/R6JCwzA8xX4?si=DirCkdQo7JEekx5B check this video out if you have the time to do so
The unit circle and the graphs of the sine and cosine functions are totally related. Check out this video to find out how one relates to the other.
i think ur confusion stems from the difference between the unit circle and the graphs of cos and sin as functions
I think this is correct
You are right, I figured it out, lets say you go back, cosine is not negative, because its still positive in the fourth quadrant, but the y goes down because its negative, and then it keeps going down because it's still negative, however cosine is cosine, its just a measure at this point, you can only have a negative cosine when you go back, but when you go back you go counterclockwise which means that cosine will be technically negative here but now instead of cos(-ΞΈ)=cosΞΈ, its cosΞΈ=cos(-ΞΈ) which is still the same thing and says that cosine is actually positive but you are going the negative direction, by the symmetric property of equality, and then everything also has to be the same, so in the y-axis, the y value would drop, which also makes the line go up back to zero and to its starting point because we are still in the fourth quadrant.
Im copying this, its literally my greatest prove ever
this might be wrong but it seems right
What is "ICT"?
In particular, is it a name for particular trigonometric identities that should be avoided?
calculator
So the double-angle indentity is fair game?
yes
i found it
what it need to be
thxcx for responding tho
Hey guys any suggestions on how to get better or master geometry
practice as many questions you can
And ur pfp is super nostalgic
ICT means Information & Communication Technology
sin(2x) = 2 cos(x) sin(x) => sin(x)cos(x) = sin(2x) / 2
1+sin2x = (sinx + cosx)Β²
Can someone explain to me how in the world sin(x+y)+sin(x-y)= 2sin x cos y how it should be, but sin(x+y)-sin(x-y)β 2cos x sin y, my book tells me that, to prove the Sum-to-Product identities, but this is impossible, because in reality it equals 0π
Do you claim that sin(x+y)-sin(x-y) does not equal 2cos x sin y? Do you have examples of x and y that make them different?
Well the book then says "Let x+y=a and x-y=b"
Huh. That's not a counterexample.
But it's not clear to me whether you're actually claiming that sin(x+y)-sin(x-y) differs from 2cos x sin y. Could you clarify, please?
I will try my best
I'm not (at this point) asking for an explanation, just for a yes or no.
Yes
Okay, then do you have an example of a particular set of values for x and y that makes the two expressions have different values?
Well, in one equation you subtract the two equations and in the other one you add both. I can conclude that the signs make the two different values different: sin(x+y)+sin(x-y)=sin(x)cos(y)+cos(x)sin(y)+sin(x)cos(y)-cos(x)sin(y)=2sin x cos y, ok
Then sin(x+y)-sin(x-y)=sin(x)cos(y)+sin(x)cos(y)-sin(x)cos(y)-sin(x)cos(y)= 0 somehow
I'm asking which particular numbers for x and y make the two expressions have different values?
Oh, there is no number, its a proof
If it's a proof then it should not be a problem for you to find some numbers that one can plug in to see a difference?
Wait, are you claiming that sin(x+y)-sin(x-y) is 0, no matter what x and y are?
Let me check
Can someone help me with this. The question is find w out calculator the exact value of cos(13pie/4)
Pls
Aha, I found something interesting, I was able to confirm that if the degrees are equal in the the x and y for both of the equations in sin(x+y)-sin(x-y), then it will of course equal 0, but if the question is like sin(x+Ο/3)-sin(x-Ο/6) there is a solution, however I was not able to calculate it, because you can't with this identity, you need to use the sum-to product identity, I figured this out by using math solver for the last question, checking for any mistakes that I may have made.
I can't prove the identity with the identity though, makes no sense
do any of you know any course books on fractals?
Finishing a book on chaos theory rn
Technically, that's false
Just because you can prove something, doesn't mean you can construct an example
can any one prove why (x-h)^2 +(y-k)^2= r^2
dud see let the pie be x cos (13x/4) which can be written as cos(x+9x/4) since x is 180 so according to the cast rule it is -cos 9x/4 then you can write this as -cos(x+5x/4) same as we did in the before it will be -(-cos 5x/4) which is cos 5x/4 again you can write is as cos(x+x/4) which is -cosx/4 since x is 180 degree we can write -cos 180/4 which is -cos 45 we know it is 1/root 2 so -1/root 2 is ans
it comes from Pythagoras
I once calculated tanx=i/root(8)
I don't even know how i did thay but it was funny
What?
Prove what about it? It's just an expression
Right. In this case I was trying to get them to plug in any numbers at all.
My geometry teacher gave me this do any of yall know how to shade it in
Some of that is logic
something like this could help you solve these, perhaps?
thats borderline giving you the answers but theres not much other than knowing what these mean and how to shade in venn diagrams
Yo guys is there any books like Stewart's calculus book for geometry?
A(ABE)=9.A(EDC) ==> A(ABE)-A(EDC) = ?
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
use similarity of ABE and DCE
Guys what's 1+1 (Boolean)
1
tru tru
hey is infinite by infinite can be written as 1
No, usually not
under normal definitions of (cardinal) infinity, infinity * 2 = infinity, infinity * 3 = infinity, and so on
that's why infinity/infinity is undefined
are you turkish?
nice problem btw
perhaps
Would be happy if someone answers
How do you calculate the area of this semicircle R1 with two fillets R2?
Well, It's kind of difficult to get an exact answer, but possible.
Important thing to note is that the line from the radius of the big circle and through the center of a small circle also passes through the point where the curve of the big circle stops, and curve of the fillet starts
To simplify set R1 = 1, set center of the big circle at origin, and only seek to find area of the right side
then solve for the center of small circle in terms of R2
Then divide the whole area into a triangle and two circle sectors
This should work
this had to be graphed I imagine (just asking)
integrals
Is this possible with geometry?
no
Then ?
you need to find a function that describes these
and integrate at correct bounds
π€―
the substract excess area
This means it is above from what I have studied
look at my account creation and server join dates
Oct 3 2025 I m older than you in this server π
But what you want to show me from this ?
same day
yeah
F1???
Yes a bit
Dedication for maths πΏ
What do you think of yesterdays Qualifying ?
I also stole that tag its clean
Not able to watch
Because of the time
Maybe
Because it will be 9:30 pm for me
I have to study also
I think I will manage somehow
Donβt study studying wonβt entertain you like max winning the title
Hope he does
I hate egoistic norris
When is his car gonna explode already
Come in chill channel
That's just not true. In fact it's harder with calculus
oh everyone is sleeping
you should recognise the expression inside the product as being one of the compound angle formulas
Yes
And use the trig formula for that product series:
tan( ΞΈ- Ο) = (tan ΞΈ-tan Ο)/(1+ tan ΞΈ Γ tan Ο)
How do I calculate R2 segment?
I think I'm on it, but I'm stuck again.
Anyone know how to do it?
like this
in this case you have $(r_2 - r_1)^2 = r_1^2 + BO^2$, so that's the length of the base of the triangle
south
south
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Thanks for the working out. Did you fix the mistakes in your original text?
I'll need some time to work through it, so I can understand it. But I'm not sure where this goes " 1/2 * BO * ...
= 1/2 * r2 * BO * sin(AOB)"
Also where did you get the number 3 and 4 from in the diagram.
they're not part of the diagram
do you know A = 1/2 ab sin C? I just used that on triangle COB
okay. So to get segment 2 would I do Sector(COD)-AOB-ABC?
just sector COD - triangle COB
I see, I'll give it a go, thank you.
no worries!
I think we got it. Does this look right. Sorry for the mad scribblings.
It's a big one.
Does anybody have any idea??
thx
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ABCD and EFBG are Squares.
If the area of triangle BNF is 9 and area of trapezoid BNEG is 27, What's the colored area
Anyone got a clue ? i suck at geometry very much
i had a idea of drawing a line from G parallel to ED
ok makes sense
we also know that FN = 1,5
cause 9 = FB * FN/2 and FB = 6
so the value of BN is going to be sqrt(38,25)
wouldn't that be FN = 3 ?
BN sqrt(45)
yea makes sens
and EN = FE - FN = 3
so AE^2 + (AB - sqrt(45))^2 = 9
so AB = 18sqrt(5) / 5
now that we have AB, we can get AE and AN, so we have the area of the triangle ANE, and value of the area of ABCD
so value of the pink area is going to be [ABCD] - 27 - [ANE]
([ABCD] is the area of ABCD)
i made a little jump there
nice π
AN = 3 * sqrt(5) / 5
yep
so AE = 6 * sqrt(5) / 5
r u sure?
AN^2 + AE^2 = 9
9/5 + AE^2 = 45/5
AE^2 = 45/5 - 9/5 = 36/5
AE = sqrt(36/5) = sqrt(36)/sqrt(5) = 6/sqrt(5) = 6 * sqrt(5)/5
then we have a mistake somewhere
i got area 0 lol
there AE = 6 * sqrt(2)/5
AB = 18 * sqrt(5) / 5 is correct right ?
i am 99% sure
ill double check
let AB be x
we have x^2 + (x- sqrt(45))^2 = 63
yeah its my mistake
AB isnt 18 sqrt(5)/5
wait let me check
ive got that AB is (3sqrt(5) + 9)/2
square roots are not needed
hey all
Im trying to solve the attached problem and im a bit confused. a cube is put in a sphere with a volume of 1.
now i understand their explanation on how they got the relationship between the length of the cube and the diameter of the sphere. however i assumed that from the center of the sphere (and cube) to the two vertices shown would be right angles and as such i can calculate the length of the side of the cube with pythagoras but that is not correct.
Can someone please explain why that is not correct as i cant see why
That's because the diagonal section of the cube is not a square but a rectangle (with the ratio of the sides sqrt(2)). So, that angle in the center is not 90
makes sense ! thank you !
Can anyone please explain to me and make a few or just one example of Midline Theorem/square?
the key says the purple area is 36
oh, yes, There is a mistake in my drawing.
Hey guys
here is a correct version
doing what on purpose?
solve for z ull see
oh LMAO
I thought you were talking about there being an issue with the question
Can someone help me with this problem, I feel so confused: vertex in (4,-3) axis parallel to the x-axis passing through (0,3)
thx!

I need to find the equation
Of the parable
Could you show the entire problem you're solving, including all instructions, please?
anyone know what is hsa? my text book uses hsa but my teacher say like hl
what would i do for 12β3??? i want to know the steps
you want to simplify 12 sqrt 3?
yes
you can think of it was 12 * sqrt 3
you can rewrite sqrt3 as 1.73
so 12sqrt3 is 20.78
ohh that's it ???
yea lol
but tysm π
ask your teacher
is it something about surface areas?
@everyone hi

