#geometry-and-trigonometry

1 messages · Page 101 of 1

obsidian harness
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The technique is always to convert the angle into a 1st quadrant angle
Otherwise you have to draw the unit circle every single time

sage igloo
#

Hello, how do you get the value of x?

native pier
sage igloo
#

I did 180-70-65 = 45

#

And then I got stuck

native pier
#

OK. Let's try a different approach

#

give me a sec I'm pulling up a pic

sage igloo
#

Oki

native pier
#

can you find this angle?

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the one in red

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-# (and maybe next time I should make it thicker)

sage igloo
#

65?

native pier
#

hmm…not exactly

sage igloo
#

Oh

native pier
#

we don't know that the big triangle is isosceles

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in fact, it isn't

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but can you use the fact that we know the two angles in the big triangle to find out this one?

sage igloo
#

Ohh so its 45

native pier
#

yeah!

sage igloo
#

Isosceles triangle has 45 right?

native pier
#

the small triangle is isosceles, yes, and so you know two of the angles already

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you can use the exterior angle theorem

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and you get x=?

sage igloo
native pier
sage igloo
#

Oki

native pier
sage igloo
#

Ahhh that one

native pier
#

mhm

native pier
sage igloo
#

So 45+45-180?

native pier
#

why -180?

sage igloo
#

90°

native pier
#

just 45º+45º

sage igloo
native pier
sage igloo
#

Is angle c also 45?

native pier
#

that isn't possible, because 45º+45º+45º=135º, and the sum of angles in a triangle is 180º

sage igloo
#

Oh

sage igloo
sage igloo
native pier
native pier
native pier
# native pier

the idea of this is that the angle outside of the triangle is <a+<b

sage igloo
native pier
barren tundra
#

some help?

sage igloo
native pier
#

one at a time pls

barren tundra
#

srry im not accustomed

barren tundra
fast pawn
#

is there a proof as to how $\sin{(x)}=\sin{(\pi -x)}$ or say $\cos{(x)}=\sin{\left(\frac{\pi}{2}-x\right)}$?

somber coyoteBOT
#

parabolicinsanity

fast pawn
#

i never really understood why, and just remembered to ask catking

native pier
#

suppose you have a point on the unit circle

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what happens if you added π? where does that point go?

fast pawn
#

the other side, anti-parallel position or something

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i'm not sure of the exact wording

native pier
#

so we know that cos is the x value, and sin is the y value

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what is the relation between the new y value and the original one?

fast pawn
#

it becomes negative, i think

native pier
#

yeah, and so that's the proof for sin(pi+x)=-sin(x)

#

u can do something similar for sin(pi-x)

fast pawn
#

oh, i think i understand now

native pier
fast pawn
#

i just remembered, perhaps the sin(A+B) and cos(A+B) expansions could help too...

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😔 i forgot about those...

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anyhow, thanks joia

native pier
somber coyoteBOT
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astraea 💫

fast pawn
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i meant like before that but thanks for the refresher

native pier
#

welcome to the mathcord btw happy

lime shard
#

AB is the diameter
P is the midpoint of CB
O is the center of the circle
PO=8
R=9.6
ACE~OKE
is it true to say EO=3.6?

#

Just had my hs finals and would like to know if I was right or wrong

scenic belfry
somber coyoteBOT
#

Iotavian

obsidian harness
somber coyoteBOT
mystic umbra
#

semantic gripe but it's true if you treat it as an equation rather than an identity

obsidian harness
#

0 = 1 is true in the trivial ring

scenic belfry
somber coyoteBOT
#

Iotavian

grave pond
#

It's not, unless the cosine is 1.

civic rock
scenic belfry
#

No sin theta only

civic rock
stoic mango
quasi crystal
#

May I have lessons on my ball cancer

civic rock
#

use chatgpt haiyaa

dark sparrow
lime crownBOT
# civic rock use chatgpt haiyaa

Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).

civic rock
#

knew it

dark sparrow
scenic belfry
grave pond
# scenic belfry Oh

You can see this because it's possible for 2sin(x) to be 2 (such as when x=pi/2), but sin(2x) is never 2.

scenic belfry
#

Oh

scenic belfry
static sapphire
#

hi

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am new to this server

worthy eagle
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@static sapphire welcome to the mathcord catking

stoic mango
static sapphire
#

yes sir

static sapphire
#

as in the guy from inside

fathom dirge
#

Please solve 4th and 5th

dark sparrow
#

or

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well actually the grades are already placed on it

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so whatever

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share your progress or working on each one

fathom dirge
full sundial
full sundial
stoic mango
fathom lynx
#

can i ask question here

civic rock
#

sure

dark sparrow
fathom lynx
#

yes

full sundial
# fathom lynx

you re given one spacing subtends 6 degrees and total spacing to be 17 and a half. You can calculate total subtended angle and then use the formula pi radians = 180 degrees to convert

dark sparrow
fathom lynx
fathom lynx
dark sparrow
#

and no, we will not give out solutions.

lime crownBOT
#

As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

dark sparrow
#

!noans

lime crownBOT
#

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.

dark sparrow
#

@fathom lynx please edit the word "bro" out of your message!

fathom lynx
#

k

dark sparrow
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thank you

#

anyway my point stands

fathom lynx
dark sparrow
#

this server is not a "do your homework/questions/whatever for you" server

fathom lynx
#

then wut is it

dark sparrow
#

but basically you're expected to put in some effort

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my suggestion in particular was meant as an intermediate step to doing the question

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and so it is with literally any question posted on here

fathom lynx
dark sparrow
#

i mean yeah you should

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you should always read the rules when joining any server

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that is... what rules are for

fathom lynx
#

yes

fathom lynx
dark sparrow
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right, some people don't like being called such words though.

#

so you gotta remember that. and if someone asks you not to call them by some word, you respect it. basic decency.

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(and you did that)

fathom lynx
#

btw dont read my status

fierce monolith
#

this shi made me laugh

winter gazelle
fierce monolith
#

look at his bio

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js funny lol

fathom lynx
scenic belfry
warped osprey
#

man I didn't know this server existed. Time to share knowledge

fathom lynx
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anyone know why I cant look into members old msg

trail tendon
#

cuz if its specific maybe cuz they never typed

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here

strong frigate
#

wait do yall know if for summer courses the high school is gonna give u a placement test to see if ur ready for the next course (example: if we’re already done with biology, will the high school give u a test before allowing u to move on to chemistry??)

also for math (if we’re not doing a summer course on math), will our high school test us on algebra and geometry before allowing us to progress onto the “advanced” algebra 2/trig course?

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just wanted to ask cuz im going to a public hs this eyar

obsidian harness
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usually you just need to pass/achieve a certain grade in the previous course to take the next course

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I don't know your school specifically

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but placement tests are for if you want to take a course earlier than your school's timetable, so you have to demonstrate knowledge of the prerequisite course material for that class

edgy cargo
#

dm me i need help on trig

obsidian harness
edgy cargo
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need help with memeorising the identity for mulas except for the pythagreas one

obsidian harness
#

what happens if you divide everything by cos^2 x?

edgy cargo
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tan

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of x

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bro idk

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im lost

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im cooked

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dont teach me

stoic mango
#

try sin(a + a)

strong frigate
# obsidian harness but placement tests are for if you want to take a course earlier than your schoo...

thanks so much for replying so quickly!!

just wanted to follow up with another qs: how does the high school evaluate a summer course (as u mentioned, I am completing a course before the actual timetable suggests - biology), and I already took alg 1 and geometry in 7th and 8th grade respectively. What im asking is if they will give me another placement test for biology (to see if im ready to move on to chem) and geometry to see if im ready for advanced algebra 2

obsidian harness
#

but yes they could equally give you a placement test covering material from those classes if they can't be bothered to do that

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your best bet is to ask your high school directly

strong frigate
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ohh ok

obsidian harness
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just email them and they'll answer

strong frigate
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yup

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thank u so much

obsidian harness
#

when I was your age I certainly wasn't as proactive

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also schools give some very clichéd advice about subject options, like "don't pick a subject just cause your friends are also doing it"

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they're treating you like babies when they say stuff like that

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there are definitely going to be people with the same maturity that deserve much better advice

obsidian harness
strong frigate
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Yes indeed

strong frigate
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i prob have forgotten everything in geo over the summer lol

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so i have to study

obsidian harness
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if I could say one thing, it'd be don't be afraid! you're going to have a lot of choices but that doesn't mean you have to get everything perfect right here, right now

strong frigate
#

oh that means a lot! Thank you!

obsidian harness
#

yeah honestly I hope you can just get through everything
I experienced a lot of injustice as a teenager that I didn't quite have the words at the time
so being in your early 20s can be a new start

strong frigate
obsidian harness
#

it sounds like you could do a lot of good things in the world
but equally don't be surprised if life just kind of rolls you over either

obsidian harness
scenic belfry
obsidian harness
#

fml I should have just said why

snow tide
#

why am i missing solutions in this isnt this the best method

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help

fathom lynx
#

I thounght it was a new discord update where ppl cant look in older msg for privacy but it simply a glich or smth

obsidian harness
somber coyoteBOT
obsidian harness
#

otherwise you're dividing by 0 and that step is not valid

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dividing is fine: you don't always need to factor it to avoid dividing

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you just need to check when it equals 0

night basin
#

Good morning, everyone. Uh, sorry to interrupt, but do you have any tips for getting started with trigonometry and geometry?

obsidian harness
night basin
#

No

obsidian harness
#

I say that cause it's hard to help if you don't post a specific question/exercise

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so I've just referred you to a place where you can both learn and practice

snow tide
obsidian harness
somber coyoteBOT
obsidian harness
#

it's a coincidence that tan^2 x = 1 doesn't introduce any new solutions

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you're actually not missing solutions

snow tide
#

ty

regal kraken
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yo chat

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what is descartes theorem

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?

spiral lodge
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Google it?

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Another name for it is "law of cosines", if this helps

rough hound
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so uh I'm learning abt trig using this YouTube video and I don't know why but I entered the same problem in the YouTube video in this calculator and the YouTube video got different answers than my calc so idk why someone help please

storm sparrow
#

Hiii guys, I'm new to this server, and for math too :P, if anyone wanna study with me, I will be really grateful. I'm currently studying deeply sines, cosines, tangents, all their inverse functions and inverse values

storm sparrow
upper echo
warped osprey
#

Y=(X+Z-1)!/(X-1)!Z! {X≥0} {Y≥0} {Z≥0} (Integers only). This is Pascal's triangle, X is the dimension, Z is the term, Y is the output

civic rock
#

geometry indeed

warped osprey
#

by dimension I am referring to the dimension of the triangular sequence, like 2d is n(n+1)/2 (triangular number sequence) 3d is n(n+1)(n+2)/6 (tetrahedral numbers) ect

warped osprey
regal kraken
#

i beleive it is used in triangles

pale sentinel
pale sentinel
#

(there has to be a Wikipedia version of JFGI...)

foggy forge
#

Hi

spiral lodge
spiral lodge
regal kraken
indigo nexus
#

its right

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it was actualy

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tan^-1

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not tan(5/4)^-1

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\documentclass{}
\usepackage{}

\begin{document}

Given:
[
\tan(\theta) = \frac{\text{opp}}{\text{adj}} = \frac{5}{4}
]

The angle (\theta) is:
[
\theta = \tan^{-1}\left(\frac{5}{4}\right)
]

Calculating:
[
\theta \approx 51.34^\circ \quad \text{(or } 0.896 \text{ radians)}
]

\boxed{\theta \approx 51.34^\circ}

\end{document}

somber coyoteBOT
#

ponkur
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

snow tide
#

is there any other way except cauchy inequality to find the range of this function?

dark sparrow
#

,rccw

somber coyoteBOT
grave pond
#

It doesn't make much sense to say "for all x, find the range of the function". The range of the function is what it is; it doesn't depend on x.

dark sparrow
#

they definitely mean "find the range of f: R -> R given by ..."

snow tide
#

yeah it's an imprecise statement but widely found in textbooks ig to specify that the domain is R in a simpler way idk

#

anyways my sir said there is another good solution but i don't seem to find it

rough herald
#

Hey all!
I'm looking for 3 teammates for HMMT (November & February)!

I’ll be focusing on algebra, so I’m looking for others who are strong in:

  • Geometry
  • Number Theory
  • Combinatorics

looking for extremely skilled individuals with serious dedication!

warped osprey
#

what is HMMT?

rough herald
#

it is a maths competition that Harvard & MIT host

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it is for high school students

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I'll participate but looking for teammates

warped osprey
#

I could try to join, I'm in high school as well

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and I'm great at math

rough herald
#

great!

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you can DM me if you want to join the team

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I'll give u 3 questions & if you answer well, we can work with each other!

solid anchor
#

Are none of these right?

silent plank
#

how are you reaching that conclusion?

solid anchor
#

Oml I got the answer -2+sqrt3 and I glanced to quickly over sqrt3-2

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Im just lowk stupid

wanton arrow
#

how can prop 3 be used to say BD is equal to AC if the only place that you can use prop 3 to do the cut is from vertex A? also im i supposed to assume that constructing DC doesnt change the angle at vertex C?

dark sparrow
#

constructing DC chops the angle at C into two smaller angles visually but you dont care about it

#

im not sure what your objection to prop 3 is. can you show how euclid states it?

wanton arrow
#

the only way to chop the less from the greater would be at vertex A on prop 6 and yeah i would think it would split the angles thats why am asking if you assume the vertex C angle stays the same

dark sparrow
#

wait

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do you claim that such a cut is ONLY legal if the two lines you're talking about already share a vertex

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y/n

wanton arrow
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yeah i am

dark sparrow
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ok you're wrong about that then

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you can cut off from either end

wanton arrow
#

i cant for the life of me figure out how to do that

dark sparrow
#

even in this prop 3, "Draw red = blue" already assumes you can copy segments by length

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which is proposition 2

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and, if you really want to spell out the construction in full,

wanton arrow
#

yes

dark sparrow
#

it's allowed to place the red segment on EITHER end of the white line.

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no privilege is given to one end of it over the other.

dark sparrow
wanton arrow
#

sure

dark sparrow
#

if you have a 10cm rod and you want to cut 7cm off of it, you can cut off that length from either end of the rod. by your logic there could be a situation where one end of the rod is privileged over the other, and only it can have 7cm cut off from it, while from the other it's somehow like cosmically or divinely forbidden to do the same

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so it just makes no sense that you'd somehow be able to cut a given length off from one end only

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capisce?

wanton arrow
#

how could you know you wanted 7cm cut off a line if you have no way to measure the 7cm unless you transfer a length, collapsing the compass

dark sparrow
#

ugh.

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okay fine, forget the measurements.

dark sparrow
#

do you agree or disagree?

wanton arrow
#

no you cant without collapsing the compass, unless it was an equilateral triangle then you could

dark sparrow
#

??

wanton arrow
#

you are measuring the length of AC with the compass then picking it up and setting it on B

dark sparrow
#

yes? is that forbidden?

wanton arrow
#

yeah forbidden

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euclid claims to do it without

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im going to have a stroke

dark sparrow
#

The compass is assumed to have no maximum or minimum radius, and is assumed to "collapse" when lifted from the page, so it may not be directly used to transfer distances. (This is an unimportant restriction since, using a multi-step procedure, a distance can be transferred even with a collapsing compass; see compass equivalence theorem.[...])

#

so says wikipedia

fathom lynx
#

better than ai

dark sparrow
#

.....

fathom lynx
#

did i stutter

dark sparrow
#

that one seems to be the one to do w/ transferring lengths

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even when our compass is collapsing

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oh

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fucking hell

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i pressed up arrow and pinged the wrong person

fathom lynx
wanton arrow
dark sparrow
wanton arrow
#

this might be hard to follow its old

cunning lion
#

you can use a newer translation if you want

dark sparrow
# wanton arrow

ok, so you agree that transferring lengths is still possible even when the compass is a collapsing one?

#

or do you want this spelled out every single time in every single proposition with every single circle drawn every single time on every single diagram

wanton arrow
#

thats how i want it but i can agree that you can transfer lengths without picking up the compass i just dont see how to do it on prop 6

dark sparrow
#

you want to spell out the full details of the construction within the setting of prop. 6?

wanton arrow
#

yes please \

dark sparrow
#

hm

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ok i admit even i can't quite follow this diagram for prop 2.

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not sure what the "describe [triangle] (prop 1)" means

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maybe you will have to show me prop 1 too

wanton arrow
#

can i dm you?

dark sparrow
#

no

wanton arrow
#

prop 1 is just an equilateral triangle

fathom lynx
cunning lion
#

more modern translation of prop 2

dark sparrow
#

also maybe you should remove the transphobic joke frrom your status.

wanton arrow
#

remove jokes????

dark sparrow
wanton arrow
#

dont look at jokes you dont like nut job, you would say some weird shit like that in the middle of a math conversation

dark sparrow
#

ok, if i'm a nutjob then i'll just leave this convo outright, bye

wanton arrow
#

bye

dark sparrow
#

i am not a "mr".

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and no, i don't have euclid's propositions memorized by number.

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if you could correct the honorific, that'd be nice.

civic seal
dark sparrow
#

lmaooooooo

civic seal
#

eudoxus

fierce epoch
civic seal
#

doesn't matter

fierce epoch
#

ok

fierce epoch
civic seal
#

we do not discuss moderation details with uninvolved users.

civic seal
fierce epoch
#

no

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my account was created like years ago

civic seal
#

I'm aware. that doesn't preclude the possibility

fierce epoch
#

I joined to seek advice

fierce epoch
civic seal
fierce epoch
#

mb

worn comet
#

yo

crystal narwhal
#

can someone help me with this

worn comet
#

is that the BYU class?

crystal narwhal
#

huh

worn comet
#

independet study for byu

#

?

crystal narwhal
#

no just middle school algebra

worn comet
#

aww

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I need help with mine to dw

crystal narwhal
#

i can do this in eighth grade so i dont have to do this in high school

worn comet
#

smart

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well

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Im stuck on mine rn

main plover
#

How do i solve these types of questions

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If i see its solution its gomma be so obvious

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But i cant solve it

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i got it

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nvm

zealous pike
#

Is it possible to find the length of the sides with the given information?

In the image there is a Rectangle ABCD whose area is 36 and the diagonal line BC length is 5

#

I've tried an equation of systems like

Let the sides be a and b

ab = 36
a² + b² = 5

But i don't think this is the way 😭

main plover
#

This is what gemini says

rancid cobalt
#

Could I try and help?

rancid cobalt
zealous pike
main plover
#

hey bro

zealous pike
#

AI for math?

main plover
#

were in the same boat here

#

the blind leading the blidn

rancid cobalt
#

Isn't ai specifically mentioned against in the rules-

zealous pike
main plover
#

oh

zealous pike
#

Don't trust AI for math, it isn't good for it

#

Mainly LLM like chatgpt and gemini

rancid cobalt
#

So the question now is whether you have enough information to figure out one side

zealous pike
#

Indeed

rancid cobalt
#

It's too large of an area to be a 3-4-5 triangle

zealous pike
#

A right triangle with hypotenuse 5 not necessarily is a 3-4-5 triangle

rancid cobalt
#

I just thought it'd be better to check real quick just in case

#

Are there any other method options you've crossed out?

zealous pike
#

If we use a system of equations, we have:

ab = 36
a² + b² = 25

a = 36/b
b² + (36²/b²) = 25
b² = (-1296 + 25b²)/b²
b =sqrt (1296+25b²)/b

No, this system seems not solvable

#

Hmmm

#

Wait a minute

rancid cobalt
#

?

zealous pike
#

b = sqrt(25 - a²)

asqrt(25-a²) = 25
a²(-a² + 25) = 625
-a⁴ + 25a² = 625
-a⁴ + 25a² - 625

yeahsully

rancid cobalt
#

yeah, and on a graph the two lines don't collide

zealous pike
#

Therefore

#

I wanna cry

#

I think that there is no solutions for this one

rancid cobalt
#

yeah, I agree there

zealous pike
#

The question asks: given the cylinder of radius r inscribed in the circle of radius 5, find the largest value of x such that its volume = 72π.

What I've tried is to find a relation to the information given.

The formula for the volume of a cylinder is hπr², where h is the height. We have that h = 2x. We want to find a value x such that 2xπr² = 72π. With some manipulation, we have:

xr² = 36

#

Maybe I'm overcomplicating this sully

rancid cobalt
#

Give me a moment to follow your thought process...

#

Okay, I see where you're going. I'm assuming there's a second equation we're making a system out of

zealous pike
#

Stop reading my mind

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If they would only give me some other angle for that triangle 😭

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Hmhmh

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Hmmhmgm

rancid cobalt
#

Oh wait

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We have something to go off of for every line of the triangle

zealous pike
#

What's it?

rancid cobalt
#

x, r, and 5

zealous pike
#

Yes

rancid cobalt
#

What equation loves having all 3 parts of a right triangle, at least as variables

zealous pike
#

I've thought about x² + r² = 5 and guessing values for x, but I don't want to guess

rancid cobalt
#

Don't forget that c is squared too

zealous pike
#

Yea

rancid cobalt
#

So you have two equations now, right?

zealous pike
#

xr² = 36
x² + r² = 25

r² = 25 - x²

x(-x² + 25) = 36
-x³ + 25x - 36 = 0

rancid cobalt
#

and now we just gotta solve that!

zealous pike
grave pond
#

That graph strongly suggests there's an integer root ...

#

(Which you were probably expected to use the rational root theorem to find).

zealous pike
#

What's that theorem

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Lemme search

#

So

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The largest possible x is 4?

rancid cobalt
#

Yes, it seems that way

#

I might be further out of my lane here than I realized, so I'll just hope someone else comes to help with the next question

zealous pike
#

Is there a faster way to solve this?blobcry

rancid cobalt
#

I usually use graphing to solve two-variable systems of equations

#

desmos graphing calculator is my best friend

zealous pike
#

I can't use a calculator in an actual test though

rancid cobalt
#

oh. That's annoying.

#

Most tests I get have desmos built-in

#

You can't even use physical calculators?

zealous pike
#

No

rancid cobalt
#

rip

tough vapor
#

Even the simplest one? Thats bad

zealous pike
#

no

#

it is a test where I have to solve each of 90 questions in less than 3 minutes

#

hmm

upper karma
#

Guys i want to know more about
Astc rule

grave pond
zealous pike
#

yea

#

gotta get myself used with polynomials then

round charm
#

So, that's the ez way x = 4.

round charm
#

HEY how about we use the pythagorean triplet formula?

#

Guys I found an easy way

viscid nimbus
round charm
#

We know that 2m, m²-1, m²+1 are pythagoream triplets. And the equation xr² = 36 suggests that x is a perfect square.

viscid nimbus
#

🙏🏼

round charm
#

Then, when I try to keep the known pythagorean number (5) in all the 3 expressions, we can see this:
m²+1=5
m²=5-1
m²=4
m=2

#

Then, 2m = 2*2=4

#

m²-1= 2²-1 = 3

#

Then 3, 4, 5 are the pythagoran triplet

#

put x = 4 and r = 3, then:
r² = 9
9 = 36/4
9 = 9

#

Hence, x = 4

#

👍

autumn briar
#

People

#

Is anyone here

dark sparrow
#

if you have something to ask then ask it; otherwise the answer will be "no, this server has been deserted for many years now"

autumn briar
#

:/

#

I see

#

I've test tmrw of trigonometry
I gotta do 9 exercise
[ I missed the theory classes of this chapter due to health issues]
So I'm kinda cooked rn

I mean what could be the best way to study if you are in that situation
[Pls don't be like js study]

dark sparrow
#

review SOH-CAH-TOA and/or trig identities as applicable

#

if you're gonna get tested on the sine law and/or cosine law, review that too

#

know your basic trig values (0, 30, 45, 60, 90°)

#

these are the most important things to know

autumn briar
#

thankyou so much ive already reviewed it at all

#

Actually i sometimes sucks at math

#

how should i approach the questions of my book

#

Like the exercise

viscid nimbus
viscid nimbus
autumn briar
# viscid nimbus what questions is it asking

Demonstrate understanding of trigonometric functions synthetically, graphically, and analytically.

Compute and manipulate trigonometric expressions confidently.

Apply knowledge of angles, quadrants, and signs to solve for unknowns.

Represent trigonometric functions visually.

Use trigonometry in context, especially with respect to measurements and problem scenarios.

#

summary of Half of the exercise

viscid nimbus
#
  1. will usually include proof of trigonometric identities using given trigonometric identities
#

such as pythagoras', reciprocals, sum, product, double-angle and half-angle

#
  1. will usually include solving trigonometric equations, how to convert radians to degrees and vice versa and what an angle is in terms of radians according to the unit circle
autumn briar
#

Damn thankyou so much for all of it

#

Should i consider watching lectures?

#

Any yt channel or something you would like to include

viscid nimbus
#

but you also need to do more challenging exercises outside of the ones he includes in his videos

#

because they are "introductory" and aren't the full scope of the exercises you will encounter

twin depot
# autumn briar Any yt channel or something you would like to include

Not the person but I really like this community college professor: math with professor V. She goes into detail and i like how she teaches https://youtube.com/@mathwithprofessorv?si=M-K9NEQrREhe4hf9. She has pretty much everything on a playlist including trig so you can see what you’re struggling with and there will be in depth explanations and a lot of examples.

split lion
#

is geomertry bad or good

#

THERE IS SO MUCH MATH

dark sparrow
obsidian harness
#

also there's the view that mathematics exists independently of our culture and society

#

so you can't really apply the labels 'bad' and 'good' to something that doesn't come from this world

upper karma
signal vapor
grave pond
#

I don't think so.

#

Perhaps Americans who (though a tradition for misleading schooling) have gotten the impression that Eucliean geometry inherently means two-column proofs and a ban on intuition.

wispy whale
#

Truth

#

Geometry is a simple topic yet when taught rigidly to an early student, becomes very unappealing

zealous pike
#

I'm trying to learn the intuitive part but for me it's being harder than the rigid/proof based one blobcry

dark sparrow
wispy whale
pale sentinel
#

I mean, #info message kinda states that the whole purpose of this server is to encourage learning

#

[that said, I do find it funny that the THINK poster's been sent three times in just over an hour opencry]

wispy whale
#

yo we're joking

#

😭

#

jokes aside avoid saying stuff like that in a channel like this, it may deter other learners if they see that someone has breezed through a topic they have a hard time understanding

lone trellis
#

hello, what do i need to know/learn for high school geometry

#

topics etc

silent plank
#

you can get a decent structure from khan

#

algebra,
definition of perimeter/area and the respective formulae for common shapes

#

parallel line theorems

lone trellis
#

alr

silent plank
#

coordinate geometry / basic graphing

jovial maple
#

Whats a free website that'll solve math all free

autumn briar
patent dirge
#

Guys need help with graphing sine and cosine functions rn 😇🙏

#

I don't understand a thing from my book

restive solstice
dire jackal
patent dirge
#

Naur

#

It's more of a discussion thing because I don't understand anything from the book

patent dirge
#

Wait

#

Idk

dire jackal
#

use desmos for the graph

vague current
#

does the book explain using a unit circle or general function?

dire jackal
patent dirge
#

I will know how to graph

#

Once I understand the whole thing

patent dirge
#

Waot

#

Wait

#

1 and -1

#

Highest and lowest so like

#

90 and 270 that's what it wants me to remember

#

Anyway I'll send the pages

#

Y'all pls explain each pages cuz like

#

Also be wary of the terms.. I'm unfamiliar

dire jackal
#

need access

#

make it publiv

#

like anyone with link can view

patent dirge
#

Wait rlly?

restive solstice
#

seems like a unit circle

dire jackal
#

same thing

restive solstice
#

access denied

patent dirge
#

.

vague current
restive solstice
dire jackal
#

same

patent dirge
#

Okay done

#

Hereee

#

Y'all dm me the explanation

#

So it wouldn't get lost

#

🩵

#

Per page

restive solstice
#

dude this book is wierd

patent dirge
#

.

dire jackal
#

very weird way to teach the graph

#

never seen it before

restive solstice
#

yeah

#

i've learnt it from the unit circle

#

this book starts with physics

haughty root
dire jackal
#

same i think

patent dirge
#

Oh-

#

So like..

dire jackal
#

i dont remember though

vague current
#

we start with the unit circle and then move on to physics... did you understand the unit circle @patent dirge and the other essentials mentioned on page 1?

patent dirge
#

Ik the unit circle

#

Sine and cosine functions at that.

restive solstice
#

the rest is easy then

patent dirge
#

But I'm here at graphing which I don't understand

#

😭

#

and I'm supposed to answer something

#

And I can't answer unless I understand the book

#

PLS

dire jackal
#

like page 5?

restive solstice
#

the book has made it complicated

#

with formula and stuff

vague current
#

do you understand the definition of amplitide, domain/range, period, vertical and horizontal phase shift?

restive solstice
#

Do you have a teacher?

dire jackal
#

for range use this formula ig

restive solstice
dire jackal
#

ye

patent dirge
#

WAIT SOMEONE DMED ME I IGNORED IT ACCIDENTALLY

#

Whoeger u are pls dm again

#

U have a dog pfp

patent dirge
patent dirge
#

That's the thing

#

It's new to me

#

Help

#

I haven't read the book yet

dire jackal
#

you need to learn functions in general first

obsidian harness
restive solstice
#

dude, try to get a physical teacher

#

because you're struggling with the basics

obsidian harness
#

the range of sin(anything) is y in [-1, 1]
multiply that range by a, when a > 0 and you get [-a, a]
and then add k to both, so [k - a, k + a]

obsidian harness
restive solstice
dire jackal
#

range is basically all the values the function can have

vague current
#

ok, maybe a more visual approach helps... amplitude=how much difference between maximum and minimum divided by 2, period: how long before the function repeats itself, phase shift: how is the function graph moved up/down or left/right compared to the sine you know from the unit circle

obsidian harness
dire jackal
#

and domain is all the values x(in this case theta) can have

obsidian harness
#

YouTube, for instance org chem tutor, isn't a bad source

patent dirge
#

Omg..

patent dirge
#

This one I tried

obsidian harness
# patent dirge

oh because this question is asking you about how to identify the amplitude, domain/range, period, vertical and horizontal phase shift?

patent dirge
#

It's kinda ironic

obsidian harness
#

yeah the question isn't asking you about how to graph trig functions

patent dirge
#

Ik how the unit circle works and cosine functions applying to unit circle

#

YET

#

I don't know how to graph

#

Oml

dire jackal
#

you dont need to make the graph for the questions

patent dirge
#

For instance

#

This looks positive

#

But because of the shift

#

It's negative

#

Like what

#

😭

obsidian harness
#

sin or cos?

restive solstice
#

@patent dirge check your DM

dire jackal
patent dirge
#

We mainly use

#

Sin and cosine

dire jackal
#

since we add na at the end of responses a lot

obsidian harness
#

either your book starts the transformation from sin(x)

patent dirge
#

Idk

obsidian harness
#

or it starts the transformation from cos(x)

patent dirge
#

I sent the file

#

😭

obsidian harness
#

sigh...

dire jackal
patent dirge
#

No

#

side eye

dire jackal
#

oki

#

since if you were i have great lectures in hindi

dire jackal
#

thats why i asked

patent dirge
#

.

#

Okay but like

#

Is the book great for learning how to graph

#

Cosine functiona

obsidian harness
#

I'd say it's decent, yes

obsidian harness
#

then I do y = (x - 5)^2

#

the new graph is translated 5 units right and not 5 units left?

patent dirge
#

I-

#

I'm trying to do it visually rn

obsidian harness
#

so the vertex of y = x^2 is (0, 0), do you agree?

patent dirge
#

Do I have a choice

#

Actually

obsidian harness
patent dirge
#

This is an independent learning thing

#

Because of the weather issues, classes are cancelled right.. and we are tasked just to read the book and answer the supplementary learning

#

That's the thing.. without a teacher I'm flopping

#

And the independent task is due tomorrow

#

Can I send videos here

obsidian harness
#

yeah

#

I'm not sure how I can help after all this so I'll just leave you for now

patent dirge
#

Okay I'll send what I understand and giv me feedback

#

ExcUSE my native language

#

I'm also like sending these to my friends

vague current
vague current
patent dirge
#

I'll watch that after

patent dirge
patent dirge
#

C is the horizontal phase shift

#

And d is the vertical shift right

#

So for horizontal ofc left and right

#

For vertical up and down

#

The shift is like the central line

#

This part is really complicated

#

Oh nvm

#

lol got it now

hollow remnant
#

Can anyone help me quickly with a sinusoidal question? I just need the answer also it’s a word problem

dire jackal
#

!da2a

lime crownBOT
#

No need to ask “Can I ask…?” or “Does anyone know about…?”—it’s faster for everyone if you just ask your question! See https://dontasktoask.com/

proper peak
#

I made a simplified proof to solve for the identity sin(beta-alpha) or any other sine subtraction equation. It only uses some basic geometry like congruence, some geometry around isosceles triangles, the d(P,r) formula, sine law, the unit circle.... Basically anything you would see up until your 10th year of school (excluding complex numbers).

mystic umbra
#

its a nice proof 👍

#

do you know how to prove it using vectors? it become extra-simplified when you use them

haughty root
ashen sentinel
#

i love geometry so much
i got 8/20 in my math test just cuz of not being able to do geometry

civic rock
#

geometry 😈

blissful cypress
#

anyone got any advice to get better at trigonometry

#

sorry if it's a dumb question

upper karma
random onyx
#

oh man where do i even start

dark sparrow
random onyx
#

yeah

dark sparrow
#

do you know any ones to do with cos(A ± B)

random onyx
#

do i want to start with given one or the tan one

random onyx
dark sparrow
#

you always start with the given

random onyx
#

gow its that easy

random onyx
#

feel so stupid rn

spring basin
random onyx
#

im stuck at every single question wtf

#

where do i start again

dark sparrow
#

well you might wanna expand sin(A-B)

#

that should give you some ideas for how to proceed e.g. how to get your hands on sin(A)cos(B)

spring basin
#

i think i got it

#

nvm

random onyx
#

i dont recall anything that changes multiplication to addition

dark sparrow
#

ok well your goal is sin(A)cos(B) - cos(A)sin(B) yes?

random onyx
#

ye

dark sparrow
#

so let's set that aside for a moment

#

now here is a crazy idea that's actually going to cook:

#

take the equation sin(A) + cos(B) = m

#

and square both sides.

random onyx
#

ohh shitt

#

im so rusty what the hell

dark sparrow
#

did you manage to proceed?

spring basin
#

i have a different method

dire jackal
#

what if you multiply m and n?

random onyx
spring basin
dire jackal
#

youd have the terms you need plus some extra

random onyx
#

and some extra terms u really dont want to see

dire jackal
#

ig yea cosacosb and sinasinb

random onyx
#

also not a good approach since its just too random

dire jackal
#

oki

random onyx
spring basin
#

wait nvm it's garbage

#

it still depends on B

haughty root
night cape
#

going to ask a silly question

#

but do i need to know my geomatry well before learning trig properly

obsidian harness
#

know all your geometry relating to triangles well, because the focus of trig is how triangles relate to the unit circle

#

so definitely revise the special triangles, the 30-60-90 and 45-45-90 ones

#

but a lot of the 'proof', like two-column proofs, is totally unnecessary for trig

night cape
#

oh awesome ok

#

sweet

#

so which subject teaches the principles of angles

#

i assume trig

obsidian harness
#

also observing similar right triangles is super useful in trig

obsidian harness
#

so all of that angles in parallel lines material belongs in geometry

#

it does help in trig but there's no shame in looking it up if you've forgotten

#

maths does tend to build on itself like stacking up a brick wall

#

but those concepts aren't the main focuses of trig

night cape
#

perfection thank you so much

#

the main reasons i want to know is because of linear algebra

#

where certrain transoformations require angles and im shit at angles

obsidian harness
#

it's not about angles specifically! it's about transformations that rotate and stretch the plane (while fixing the origin)

#

for those rotational transformations yes trig is very important

obsidian harness
#

so honestly just leave geometry behind if you're ready

night cape
#

ohhhh so the sin60 and all that

obsidian harness
#

I think that the book Linear Algebra Done Right by Axler also has a foundations chapter at the very beginning

night cape
#

thats not geomatry

obsidian harness
night cape
#

oh sick!

obsidian harness
#

it is a part of geometry yes but taught separately

night cape
#

then is there really anything i need from geomatry or can i just focus trig?

obsidian harness
night cape
#

perfect thank you south pandahugg

obsidian harness
#

if you're really missing anything don't be afraid to look back and revise if you need it

#

but that's on a "if you need it to understand trig" basis

night cape
#

of course holoyay I did that with algebra

obsidian harness
#

np!

night cape
#

went all the way back to 4th grade for that one

#

and now i understand equations, kinda haha

proper peak
# mystic umbra do you know how to prove it using vectors? it become extra-simplified when you u...

For the sine identity I haven’t learned anything that really comes to mind as sufficient enough to prove it, I figure you’re talking about matrices and matrix multiplication or something else of the linear algebra field. I made this proof based only on my current knowledge of mathematics up until the 10th year (here it is 4th year of high school Belgium, mostly ages 15-16). I will be teaching myself some new stuff this summer.

obtuse moth
#

Where is a good place to get a really complete understanding of trignonometey before starting calculus?

#

I checked the pins but I dont see much

deft sail
#

So when I learned Trig, I didn’t really learned it in school so I have no textbook

obtuse moth
#

I bought algebra and trigonometry by sullivan but I think the book is too slow paced for me as I learned a decent bit of trig and algebra from hs

deft sail
#

But I used Professor Dave’s Playlist and an app that has Trig on it

obtuse moth
#

I would also want to get a better understanding of algebra

deft sail
#

Don’t use the app

obtuse moth
#

But im decent at algebra, I just want to learn trig better

#

Before I start learning calc

deft sail
#

Yeah I would just use Professor Dave’s math playlist

obtuse moth
#

Thanks man

#

Are there any places where I can find practice problems with solutions?

deft sail
#

No prob, and just in case he doesn’t have precalc to my Knowles

deft sail
obtuse moth
#

Would be cool if there was a site with practice problems for all branches of math

deft sail
#

On what I know, unfortunately not :(

#

But there was one website

obtuse moth
#

Thats okay!

deft sail
#

I just don’t know the name

obtuse moth
#

Thank you for the advice regardless

deft sail
#

You’re welcome

modern wharf
obtuse moth
modern wharf
obtuse moth
#

AOPS

#

They are books

#

If im not mistaken

modern wharf
#

there is a website and a trainer on there

#

alcumus

#

i used it quite a bit and it’s pretty nice

obtuse moth
#

Ohhh I see

green latch
#

hello fellas

#

what a great day to be an engineer+math major]

rich wagon
#

not sure if this is the right place to ask for this so please correct me if this is wrong. But is there a way to get desmos to give me this number as the fraction pi/2?

wintry ibex
rich wagon
#

yikes

#

why can it convert some decimals to fractions and not others though

#

but then I add 1 more digit

#

and it wont work

pale sentinel
#

Because pi is definitionally not rational

#

So it can't be written as a fraction

#

Further, it has a memory limit

rich wagon
#

but it can be written in ways like (2pi/4)

pale sentinel
#

Again, PI is not rational

#

So neither is any fraction a*pi/b where a and b are integers

rich wagon
#

so desmos just isnt good enough to convert it?

#

because can't like AI calculators do it

pale sentinel
#

All AIs are merely interpolative

rich wagon
#

interpolative?

pale sentinel
#

And further, MLM AIs are just interpolative of written works

#

As in, they take in shitloads of written works as a corpus of information, then respond to a prompt in a manner that mimics the corpus

rich wagon
#

hmm

#

ok got it

pale sentinel
#

So if the corpus contains shitloads of "sin pi = 0", then when you ask it to evaluate sin pi, it will give you 0

rich wagon
#

would still be so nice if calculators could do it

pale sentinel
#

This is the crux of using AI here

pale sentinel
#

It's no divine entity

#

This is why maths is still a school subject after thousands of years

rich wagon
grave pond
#

That's why it's important to learn how the calculator does it, to demystify it at least a little.
Unfortunately, understanding how calculators handle trig functions (in the sense of "how can we be sure the results it gives are right") takes a lot more mathematics than it does to learn to use trigonometry for ... um ... "practical" tasks.

hybrid pivot
#

Hey Here is simple task May you solve the problem. That's easy
It takes for two minutes.
a + b = a * b ===>>>> a != b ~~a ,b ??

native pier
lime crownBOT
visual flume
#

geometry is so tuff

#

anyways is this a good idea?

#

my 7 y/o brother cant hop off roblox
i set his time limit as fibonacci sequence
i told him its the first few terms of the fibonacci sequence (there is no way he is able to spell it out in the next 2 years)
i wrote down the formula for it
if he figures it out by the end of this month he can play whenever he wants
if he doesnt im changing the psw

lime crownBOT
dark sparrow
knotty quiver
#

does LLM mean Large Language Model?

#

if it does, could there be a Medium Language Model and that's what MLM stands for?

#

the closest relevant acronym i can find online is Masked Language Model

upper karma
mossy mirage
#

hi can anyone help me prove this identity

dark sparrow
mossy mirage
dark sparrow
#

ok then don't multipost

mossy mirage
#

sorry 😭

agile glen
edgy wagon
#

Why is the altitude of 30*40/50?

pearl hinge
#

Try proving that triangle ABD and triangle BDH r similar

pearl hinge
edgy wagon
#

That makes sense,

#

Thank you!

pearl hinge
#

Np

glossy flare
#

<@&286206848099549185>

native pier
lime crownBOT
clear sleet
edgy wagon
#

It is on the AoPS website,

jagged sonnet
#

Hi, not asking help for any specific question but more so on like how I'd study this topic, if I needed to learn the unit circle what's the best way to tackle it? I've always struggled with it

#

To solve like questions like these or anything that needs trig

silent plank
#

start with learning how to derive the ratios for the special angles

#

that pretty much gives the first quadrant of the unit circle

#

you can get the rest of the unit circle from reflections

#

which also gives you the supplementary and odd/even identities

#

(also learn the conversion between radians and degrees)

twin depot
#

Lowkey a banger

#

Or you could use the finger trick (if you have 6 your fucked😭 /j)

#

Like what Rauomenganato said as long as you know the first quadrant then you can figure out the rest

haughty root
solid needle
#

honestly just learning your special triangles and how sin and cos actually work is way easier than memorizing these values

#

youre just making more work for yourself and not understanding the material as well in the process

#

oh that is what you're saying, nvm

dense escarp
#

Is this channel for general discussion of geometry? I’m new

civic rock
#

yes

slow pasture
#

i just memorized it

#

by hard practice

twin depot
#

Seeing shit when I needed the most is crazy

slow pasture
#

2500 hours of math

slow pasture
#

will skill you up

twin depot
#

Grinding through my precalc book🫩

slow pasture
#

😔

#

im israeli.

#

our edu system is at the rubble

twin depot
snow tide
#

yo theres such a short method just divide by cos and u get cosx/(1+sinx) and then rationalise and its done in 3 lines lol

slow pasture
#

i remember 30 and 60 together.

dense escarp
snow tide
snow tide
#

ik like 100 diff identities but the useful ones smh

slow pasture
#

proceed mathing.

civic rock
#

either memorize by experience if you have good memory
or just do the hand trick or whatever trick if you struggle to remember

twin depot
snow tide
twin depot
#

Do whatever helps you🤔

dense escarp
#

When did you guys start studying mathematics?

slow pasture
slow pasture
dense escarp
#

Cool

slow pasture
dense escarp
slow pasture
dense escarp
#

Sounds cool

twin depot
# dense escarp When did you guys start studying mathematics?

When my 7th grade teacher was absolutely terrible at teaching (I barely passed my state exam😭 and many of her students failed and most of them were hard working) I hated math but my algebra 1 teacher the next year made me love it a lot cuz she teached well and I guess now few months later I’m learning something what I hate now I love😂